The AN/PSN-13, known as the Defense Advanced GPS Receiver (DAGR), is a compact, handheld military GPS receiver that delivers secure positioning, navigation, and precise timing data for dismounted soldiers, vehicular operations, sensors, and weapon systems in contested environments.[1] Developed by Rockwell Collins (now part of Collins Aerospace), it features a dual-frequency (L1/L2) RF front end for robust satellite signal tracking, advanced anti-jam capabilities, and integration with the Selective Availability Anti-Spoofing Module (SAASM) to access encrypted military GPS signals while resisting spoofing and interference.[2] Weighing approximately 1 pound (0.45 kg) and offering over 14 hours of battery life, the DAGR supports all-in-view navigation from up to 12 satellites and includes interfaces for laser rangefinders and situational awareness displays.[1]Introduced as the first U.S. handheld GPS with SAASM security, the AN/PSN-13 entered production in 2004 and began fielding to the U.S. Army, Air Force, and other services that fall, rapidly becoming the standard for joint military operations.[3] It replaced legacy devices like the Precision Lightweight GPS Receiver (PLGR) by providing enhanced accuracy, faster acquisition times via a holdover precision time source, and compatibility with encrypted P(Y)-code signals for denied GPS scenarios.[2] By 2010, over 250,000 units had been delivered to U.S. forces, with ongoing contracts supporting production and upgrades into the 2020s.[4]The DAGR's design emphasizes ruggedness, meeting MIL-STD-810 standards for environmental resilience, and it has been widely adopted by allied nations under foreign military sales.[5] Recent enhancements include software improvements for extended functionality, as seen in variants like the AN/PSN-13A.[6] These upgrades ensure the AN/PSN-13 remains a critical enabler for navigation warfare. As of 2025, the DAGR is being succeeded by M-Code-capable receivers such as the NavGuide.[7]
History and Development
Origins
The development of the AN/PSN-13 Defense Advanced GPS Receiver (DAGR) was driven by the need for a more secure and robust handheld GPS system to address vulnerabilities exposed in earlier military operations, particularly the susceptibility of single-frequency GPS signals to jamming during the 1991 Gulf War.[8][9] These limitations highlighted the risks in GPS-denied environments, where interference could disrupt navigation for ground forces relying on systems like the Precision Lightweight GPS Receiver (PLGR), which was fielded starting in the early 1990s and operated solely on the L1 frequency, leading to longer signal acquisition times and reduced performance under electronic threats.[10][3]Rockwell Collins initiated work on the DAGR under U.S. Department of Defense contracts in the early 2000s, with the U.S. Global Positioning System Joint Program Office awarding a $6.8 million contract on February 6, 2001, to advance secure GPS receiver technology.[11] Initial production contracting followed in 2003, focusing on integrating dual-frequency (L1 and L2) capabilities to improve accuracy and resilience over the PLGR's single-frequency design.[12] A key technological advancement was the incorporation of Selective Availability Anti-Spoofing Module (SAASM) version 3.2, enabling secure decoding of the encrypted P(Y)-code military GPS signal for anti-spoofing and enhanced protection against jamming.[13][14]The DAGR was specifically designed to replace the PLGR, which had become outdated by the early 2000s due to its limited frequency support and slower acquisition in contested environments, ensuring U.S. forces had a more reliable positioning, navigation, and timing tool for modern warfare.[10][3] Production entered full swing in March 2004, marking the transition to field deployment and addressing the DoD's push for improved anti-jam features in handheld receivers.[15]
Production and Deployment
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) entered production in March 2004 under contract with Rockwell Collins, following the company's selection earlier that year for manufacturing the device.[16] By September 2005, Rockwell Collins had delivered the 40,000th unit, marking rapid scaling in output to meet military demands.[17]By the end of 2006, the U.S. Army and various allies had placed orders for approximately 125,000 units through contracts totaling over $300 million, reflecting widespread procurement across U.S. joint forces. By 2010, over 250,000 units had been delivered to U.S. forces.[18][4] Deployment of the DAGR commenced in 2004, with initial fielding supporting operations in Iraq and Afghanistan, and achieved full integration by 2008 among U.S. joint forces as well as select NATO allies subject to export controls.[17][19]The base model carries the National Stock Number (NSN) 5825-01-516-8038, while the AN/PSN-13A variant is designated 5825-01-526-4783; the approximate unit acquisition cost to the government is $1,832.[20] Primary production remained with Rockwell Collins until its 2018 acquisition by United Technologies Corporation, which merged with Raytheon in 2020 to form RTX; the military GPS business, including DAGR support, was subsequently acquired by BAE Systems in July 2020, with ongoing sustainment contracts active as of 2025.[21][22]
Design and Specifications
Physical Design
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) is a compact handheld device designed for portability in tactical environments, weighing 0.94 lb (0.43 kg) with batteries installed.[23] Its dimensions measure approximately 6.4 inches in height, 3.5 inches in width, and 1.6 inches in depth, enabling it to fit securely into a standard 2-magazine ammo pouch for convenient soldier carry during missions.[24] Constructed from durable polycarbonate/PBT polyester blend materials, the unit emphasizes ergonomics with a form factor that balances functionality and ease of one-handed operation in the field.[24]The DAGR's ruggedized build complies with MIL-STD-810 standards for resistance to environmental stressors, including shock, vibration, and extreme temperatures ranging from -32°C to +70°C during operation.[25] It is also engineered for water resistance suitable for immersion in tactical conditions, ensuring reliability in rain, dust, or mud without compromising performance.[23] This robust construction supports prolonged exposure to harsh field conditions while maintaining the device's lightweight profile for dismounted operations.Power is supplied by four AA batteries, such as lithium L91 cells or BA-5800/U packs, delivering up to 14 hours of continuous operation depending on usage and battery type.[25] The system includes low-battery indicators on the display and provisions for external DC power input via cable, allowing extended runtime when connected to vehicle or aircraft sources.[23] The user interface centers on a 2.4-inch graphical LCD screen with adjustable backlight for visibility in low-light scenarios, complemented by a thumb joystick for menu navigation and dedicated buttons for quick access to core functions.[26]The standard kit includes essential accessories such as a protective carrying case, remote antenna (e.g., RA-1), data cable, and DC power cable to facilitate integration.[23] Its modular design supports mounting kits for vehicle or aircraft installations, enhancing versatility across operational platforms without altering the core handheld ergonomics.[27]
Performance Specifications
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) operates on dual frequencies, L1 at 1575.42 MHz and L2 at 1227.60 MHz, enabling precise signal processing through ionospheric correction and improved accuracy in challenging environments.[25] It features 12-channel parallel tracking, allowing simultaneous acquisition and monitoring of all visible GPS satellites for robust all-in-view navigation.[14]Under optimal conditions with Selective Availability Anti-Spoofing Module (SAASM) encryption enabled, the DAGR achieves a time to first fix of less than 100 seconds for a cold start and less than 22 seconds for a warm start, facilitating rapid positioning in dynamic operational scenarios.[26] Positional accuracy reaches less than 3 meters Circular Error Probable (CEP), providing high-confidence location data for tactical applications.[28] Velocity accuracy is 0.4 m/s (3D, 95%).[26] The receiver handles speeds up to 250 m/s (≈486 knots) and altitudes from -400 m to +9,100 m (≈-1,312 to 29,856 feet), ensuring performance across a wide range of military mobility requirements.Battery life for the DAGR, powered by four AA lithium batteries, extends to more than 14 hours in continuous tracking mode, balancing endurance with operational demands.[26] It operates effectively in temperatures from -32°C to +70°C, demonstrating resilience in extreme environmental conditions. The standard update rate is 1 Hz, with configurable options up to 10 Hz for high-dynamic applications such as fast-moving vehicles or aircraft.[29]
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) provides robust navigation tools tailored for tactical environments, enabling precise positioning and route management. It supports the storage of up to 999 waypoints, allowing users to save and retrieve key geographic locations for repeated navigation tasks. Route planning capabilities include creating paths with up to 1000 legs across up to 15 routes, facilitating multi-segment journeys, while go-to navigation directs users to selected waypoints with graphical map overlays for enhanced situational awareness.[30][14]The device operates in multiple navigation modes to ensure reliability under varying conditions. Continuous tracking mode maintains real-timesatellite acquisition for ongoing position, velocity, and time (PVT) solutions. Dead reckoningmode leverages internal sensors, such as the compass, to estimate position during brief GPS signal outages. Differential GPSmode incorporates correction data to achieve sub-meter accuracy when available.[30][31]For system integration and analysis, the DAGR outputs data via NMEA 0183 compatible interfaces, supporting connectivity with external devices like displays or computers. It also records mission data logs internally, capturing track history and events for debriefing and performance review post-operation.[14][30]Map functionality is supported through loading vector and raster formats via SD card, enabling customizable overlays on the device's display. Position is presented in multiple grid reference systems, including Military Grid Reference System (MGRS), Universal Transverse Mercator (UTM), and latitude/longitude, to align with operational requirements.[30][14]Supplementary features bolster user effectiveness by displaying real-time metrics such as ground speed, magnetic heading, elevation above sea level, and coordinated universal time (UTC). Safety-oriented features include a man-overboard function to manually store the current position as a waypoint for recovery, and proximity warnings for approaching predefined zones or waypoints.[30]
Security and Anti-Jam Features
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) incorporates the Selective Availability Anti-Spoofing Module (SAASM), with versions including 3.2 in early models and 3.7 in later upgrades, which enables secure decoding of encrypted P(Y)-code signals to provide robust anti-spoofing protection against unauthorized or falsified GPS transmissions.[32] This module ensures that only authenticated military GPS signals are processed, leveraging dual-frequency L1 and L2 tracking for enhanced signal integrity in contested environments.[14] While the DAGR is not natively equipped for modernized M-code signals, it supports compatibility through integrated accessories like the Distributed Device (D3) configuration, allowing upgrades for future signal processing.[33]To counter jamming threats, the DAGR delivers 41-44 dB jamming-to-signal (J/S) resistance while maintaining full tracking (state 5), and 24 dB during signal acquisition, enabling reliable operation amid interference.[26] Optional controlled reception pattern antennas (CRPA) and the Vehicle Anti-Jam Accessory (AJA) further bolster this capability by dynamically nulling jammer sources when deployed in vehicular mounts.[2]Communications security (COMSEC) for the DAGR is managed through National Security Agency (NSA)-provided cryptographic keys, which are loaded via secure devices such as the KYK-13 or AN/CYZ-10 using a dedicated crypto keyfill cable.[2] As a controlled cryptographic item, the DAGR falls under International Traffic in Arms Regulations (ITAR) export controls, restricting its distribution and requiring approved vendor handling, including destruction of obsolete units to prevent key compromise.[34] Firmware updates are restricted to secure, authenticated channels to maintain integrity.[35]For operational security, the DAGR supports emergency key zeroization to erase cryptographic variables (CV) upon command, safeguarding sensitive data in case of capture or compromise.[30]
Operational Use
Military Applications
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) serves as a primary navigation tool for dismounted infantry units in U.S. forces, enabling precise positioning for artilleryfire support targeting, convoy route planning, and search-and-rescue operations during major conflicts such as Operation Iraqi Freedom (2004–2011) and Operation Enduring Freedom in Afghanistan.[36][37] Its secure, Selective Availability Anti-Spoofing Module (SAASM)-enabled GPS signals provide real-time location data critical for tactical maneuvers in dynamic combat environments, where accurate geolocation reduces fratricide risks and enhances mission effectiveness.[14]DAGR integrates with broader command and control systems, such as the Force XXI Battle Command Brigade and Below-Blue Force Tracking (FBCB2-BFT), to share position data for improved situational awareness among friendly forces on the battlefield. While primarily a handheld device, it supports vehicle-mounted configurations for integration into platforms like armored vehicles, tanks, and aircraft, allowing seamless navigation and targeting in mechanized operations.[38] Its rugged design withstands extreme field conditions, ensuring reliability during prolonged deployments.[14]Under the U.S. Foreign Military Sales program, DAGR has been supplied to allied nations, including Australia, facilitating interoperable navigation capabilities in joint operations. In recent applications, Australian and U.S. forces tested DAGR in GPS-degraded environments during 2024 joint exercises in New Mexico, simulating electronic warfare jamming to evaluate its resilience for use in contested battlespaces, including with platforms like Bushmaster vehicles and tanks.[38] These tests highlighted its performance under simulated denial conditions, informing enhancements for long-range strikes and autonomous systems.[39]Despite its advancements, DAGR's effectiveness depends on line-of-sight access to GPS satellites, which can be disrupted in urban canyons, tunnels, or jammed scenarios; in such cases, it is often supplemented by inertial navigation systems in integrated platforms to maintain positioning continuity.[40][41]
Interface and Usability
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) employs a user interface with a joystick and 15-button keypad for menu navigation, data entry, and selection, enabling operators to scroll through options and edit waypoints efficiently. The display features dedicated windows for pages, toolbars, messages, and pop-ups, incorporating intuitive icons to support graphical navigation and status monitoring. Primary language support is in English, with the interface designed for quick access to position data and satellite acquisition status.[30][31]Operator training for the DAGR typically involves a familiarization course using official resources, including the Operator's and Maintenance Manual (TM 11-5820-1172-13), which details setup procedures, menu navigation, troubleshooting steps, and interpretation of error codes such as satellite signal loss or battery warnings. The manual emphasizes hands-on practice for acquiring fixes, entering waypoints, and loading crypto keys, ensuring proficiency through practice for basic and advanced features like route planning. Pocket guides and video tutorials further aid initial training by demonstrating power-on sequences and mode selections.[42][31]Usability is enhanced by features such as an adjustable backlight, activated by holding the BRIGHTNESS/MENU key, which improves visibility in low-light conditions without excessive battery drain. Audible alerts are provided for key events like waypoint arrival or signal degradation, displayed alongside visual cues in the message window to minimize operator distraction. The compact, ergonomic design facilitates one-handed operation, with dual-function keys (short press for primary actions, long press for secondary) reducing the need for two-handed input during movement. These elements lower cognitive load relative to the predecessor PLGR's text-only interface, allowing faster interpretation of graphical maps and navigation pointers.[30][31][43]Maintenance procedures focus on field-replaceable components, including the battery pack—installed by aligning its tab with the DAGR slot and securing the latch—and external antennas for quick swaps in operational settings. Firmware updates and crypto key loading are performed via secure devices like the KYK-13 key loader, ensuring compatibility with encrypted GPS signals without requiring annual calibration. These user-serviceable aspects support sustained reliability, with a mean time between failures of 10,000 hours in rugged environments.[31][28][26]Military operators have consistently praised the DAGR for its reliability during 2000s-era deployments, citing its proven performance in providing precise positioning amid jamming threats and its intuitive handling in high-stress scenarios. Feedback highlights the device's durability and ease of integration into tactical workflows, though the compact screen size can pose visibility challenges in direct sunlight, often addressed with optional protective hood accessories.[14][40]
Comparisons
To PLGR
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) was introduced in 2004 as a significant upgrade over its predecessor, the Precision Lightweight GPS Receiver (PLGR), which entered service around 1990. While the PLGR provided reliable single-frequency (L1) GPS capabilities for military users, the DAGR advanced to dual-frequency (L1/L2) operation, enabling better accuracy and ionospheric error correction in challenging environments.[44][28]Key differences in design and performance are highlighted in the following comparison:
Full SAASM for encrypted P(Y)-code and anti-spoofing
These enhancements made the DAGR more portable and user-friendly, fitting easily into a soldier's pocket or ammo pouch compared to the bulkier PLGR. The DAGR's faster satellite acquisition stemmed from advanced correlator technology, reducing wait times in dynamic operations. Additionally, the inclusion of SAASM provided robust encryption absent in the PLGR, addressing evolving security needs for precise positioning in contested areas. Overall, the DAGR improved portability by over 2.5 times and acquisition speed by approximately 3-6 times, mitigating limitations observed in earlier GPS systems during 1990s conflicts like the Gulf War.[45][3][14][46][26][47][14]
To Successors
The AN/PSN-13 Defense Advanced GPS Receiver (DAGR) is being succeeded by next-generation assured positioning, navigation, and timing (A-PNT) systems designed to enhance resilience in contested environments. BAE Systems introduced the NavGuide GPS receiver in June 2023 as a field-installable drop-in replacement for the DAGR, enabling quick integration into existing mounts and accessories with minimal mission interruption.[48][49] The NavGuide supports M-Code signals for improved anti-jam and anti-spoofing capabilities, building on the DAGR's baseline security features while offering a modernized 3-inch full-color graphical user interface, moving maps, situational awareness functions, and over 14 hours of battery life.[49]For mounted applications, the U.S. Army's Mounted Assured Positioning, Navigation, and Timing System (MAPS) Gen II, developed by Collins Aerospace, serves as a key successor to the DAGR in ground vehicles such as Stryker tanks.[50] This two-unit system, comprising the NavHub-100 processor and MSAS-100 anti-jam antenna, replaces legacy DAGR receivers by maintaining compatible interfaces while adding M-Code and Y-Code support, modernized signal tracking for GPS integrity, and multi-sensor integration for inertial navigation in GPS-denied scenarios.[50] Additionally, software updates like the Resiliency Software Assurance Measure (RSAM) have been applied to existing DAGR units to boost survivability against jamming, providing partial compatibility enhancements without full hardware replacement.[51]These successors address evolving threats by prioritizing M-Code's higher-power signals and beamforming for superior anti-jam performance over the DAGR's L1/L2 P(Y)-code limitations.[49][50] Limited production of the NavGuide began in 2024, with full-scale manufacturing in 2025 at its Cedar Rapids facility. Deliveries to customers began in 2025. As of 2025, initial deliveries of the NavGuide have commenced, supporting the phased replacement of DAGR units in joint forces.[49][52]A civilian counterpart to the DAGR is the Polaris Guide from Rockwell Collins (now Collins Aerospace), a non-secure handheld GPS receiver using Standard Positioning Service (SPS) C/A-code signals without Selective Availability Anti-Spoofing Module (SAASM) encryption.[25] It shares the DAGR's form factor and interfaces for interoperability in federal and commercial applications, delivering real-time positioning with over 14 hours of battery life and support for up to 999 waypoints.[25]