FAQs

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General FAQs


What is PNT?

  • PNT stands for Positioning, Navigation, and Timing, where Positioning is the ability to determine accurate and precise locations, Navigation is the ability to maneuver with accuracy and precision, and Timing is the ability to acquire and maintain accurate and precise time.

Where can I get further information about GPS?

  • To aid further research, the Department of Homeland Security established the Navigation Center of Excellence (formerly Navigation Information Service) as a point of contact for GPS users. Operated and maintained by the U.S. Coast Guard, the NIS can be reached at (703)313-5900 seven days a week, 24 hours a day, and at www.navcen.uscg.gov.

What is the difference between military and commercial GPS receivers?

  • The difference between a military GPS receiver and any commercial model is the internal cryptographic device that enables a military receiver to access the Precise Positioning Service (PPS) signal. Operating a military GPS receiver without an active key greatly reduces the performance of the device and limits the receiver’s ability to the Standard Positioning Service (SPS) only.

Assured PNT FAQs


What is Assured Positioning, Navigation, and Timing?

  • Assured Positioning, Navigation, and Timing (A-PNT) is secure, authenticated access to PNT information.

What are the benefits of Assured PNT?

  • Reduces PNT requirements inefficiencies and redundancies
  • Decreases Warfighter vulnerabilities
  • Provides an affordable migration path to Military Code (M-Code)

How will Assured PNT support soldiers in the field?

  • A-PNT will provide Army Forces with unhindered access to trusted PNT information under conditions where space-based PNT may be limited or denied. The overarching A-PNT program consists of a set of complementary subprograms that together provide a cumulative effect to meet the overarching A-PNT requirement.

DAGR FAQs


What is the most current version of DAGR software?

  • The current software version numbers are listed below, but note that the file in the Download Library contains everything needed for both versions listed. The installer will select and load the correct software.

                                           Software Version             RC PN                          NSN
           AN/PSN-13A           984-3006-009            822-1873-002       5825-01-526-4783
           AN/PSN-13B           811-4960-004            822-1873-003       5825-01-590-9534
 


I have an AN/PSN-13A DAGR.  What can I do to get it upgraded or exchanged for an AN/PSN 13B DAGR?

  • No. There is no logistics/supply support for the AN/PSN-13B in the Army. There is also no need to upgrade or exchange since the AN/PSN-13A and AN/PSN-13B DAGRs are equal in form, fit, function, and performance.

How do I send my DAGR in for repair? (Army users)

  • DAGRs are no longer sent to the DAGR Original Equipment Manufacturer (OEM), BAE Systems. The Army performs DAGR repairs now by replacement. CECOM has transitioned the DAGR ordering process from the DAGR Item Manager (DAGR Mailbox) to the standard Army supply system. The DAGR Mailbox is no longer being used/monitored. Effective 10 February 2020, you must use G-Army to process your unserviceable turn-ins and/or place requisition(s) for new DAGRs. In addition, turn-in must be taken to your Supply Support Activity (SSA) or Property Book Officer (PBO).

 


How do I tell if my Army GPS DAGR receiver warranty has expired? (Army users)

  • There is no needed to determine if the warranty expired. When DAGRs were repaired by the DAGR OEM, it was important to determine if the repair was going to be performed under the “warranty” (OEM funded) or as a warranty exclusion (CECOM funded). For the Army, repair of DAGRs is by replacement via the Army supply system (G-Army).

 


I lost my DAGR.  What do I need to do in order to get a replacement? (Army users)

  • A military GPS receiver is considered a Class VII End Item (sensitive item) and should be handled accordingly. In most cases, a Report of Survey is the appropriate means of determining accountability for a lost GPS receiver. CECOM-ILSC is the action office to provide replacements for lost DAGRs. Replacement action is only taken upon receipt of a copy of a completed Report of Survey. Individual commands cannot requisition replacement GPS receivers from the general supply system since CECOM controls new stock and exercises control over all depot stock through the service Item Manager. Contact us at usarmy.apg.peo-iews.mbx.pd-pnt-support@mail.mil and we will connect you with the correct POC.

What is the latest version of Technical Manual for military GPS receivers?

  • GPS Receiver Technical Manuals are available for downloading from LOGSA (select the ETM/IETM radio button and click Enter Site). Users should download the official copy, and answer yes when asked if they want to be notified when an update is issued. That will ensure that you always have the latest official copy.

What GPS training materials are available and how do I get them?

 


Is the DAGR a sensitive item?

  • Yes and No. The DAGR is categorized in supply terms as a high-value easy-to-pilfer item that should be afforded a level of security appropriate to the mission data that may be loaded. However, because the DAGR is unclassified even when keyed, it is not categorized as a controlled cryptographic Item (CCI).

 


Can we transfer data to multiple DAGRs? 

  • Data:
    • Yes, you can transfer selected data over a selected receiver port from one DAGR to another. You have a variety of options (see the full discussion in TM para. 11.2.2.3):
      • All data except maps and waypoint mission data
      • Waypoint and mission data
      • Satellite data, initialization data, customized navigation pages, maps etc.
  • Reprogramming data:
    • It depends which part of DAGR software has been updated by the reprogramming process. Certain modules of DAGR software are restricted from DAGR-to-DAGR transfer for security reasons. The MWO/TCTO directing each specific software update will identify whether DAGR-to-DAGR reprogramming is possible on a case-by-case basis.
  • Crypto keys:
    • No. For security reasons, crypto keys must be loaded individually to each DAGR and cannot be transferred from one to another (refer to TM para 11.2).

 


How do I get map software and maps for DAGR?

  • You need two items: the DAGR Map Loader software and the specific digital maps for your Area of Operation.

The DAGR Map Loader software is available for download from the Download Library.  Maps are not available at the PM PNT website. Maps are available from the Army Geospatial Center (AGC) website.  Send your map request to the DAGR Team at DLL-AGC-CMB@USACE.ARMY.MIL.


How do I load maps from the laptop?

  • Download and install the DAGR Map Loader software from the Download Library or AGC website and download the desired maps to a drive on your PC (see the FAQ for downloading maps). Once installed, the DAGR Map Loader will place a DAGR Map Loader icon on your desktop. Double-click this icon to launch the program. Reference: DAGR Map Loader Software, part number 984-3095-010, dated March 2020.

 


Is the map’s datum important?

  • Yes. You should always set your GPS unit's datum to match the datum of the map you are using. Every map that shows a geographic coordinate system such as UTM or latitude and longitude with any precision will also list the datum used on the map.

The GPS system uses an earth-centered datum called the World Geodetic System 1984 or WGS 84. WGS 84 was adopted as a world standard from a datum called the North American Datum of 1983 or NAD 83. For all practical purposes, there is no difference between WGS 84 and NAD 83. Most USGS topographic maps are based on an earlier datum called the North American Datum of 1927 or NAD 27. Some GPS units subdivide this datum into several datums spread over the continent. In the Continental United States use NAD27 CONUS: within CONUS, the difference between WGS 84 and NAD 27 can be as much as 200 meters.


How can I extend the life of my batteries?

  • The basics are spelled out in the Technical Manual. After you get an initial fix, switch to standby mode to conserve battery power.
  • Remember to make use of the Battery Page under the Receiver Setup menu.
  • When you replace primary batteries, go to the Battery Page to:
    • Update battery installation date
    • Update battery type
    • Update rechargeable fields
    • Reset the battery used time
  • When you replace the memory battery, go to the Battery Page to reset the memory battery installation date (refer to TM para 7.6).

 


How do I make my DAGR stay on for more than 5 minutes?

  • A DAGR that keeps "turning itself off" is likely in Auto-Off Mode, which can be turned on or off. When you turn it on, you can set the timer within a range of 15 seconds to 30 minutes, at the end of which the receiver will turn off. The Auto-off mode saves power when operating in handheld mode (refer to TM para. 7.5.2.1.1).

 


How does my internal compass work when I am tracking satellites?

  • The DAGR contains an electronic compass accurate to about 6 degrees for determination of azimuth and track when the DAGR is not moving or is moving slowly. Once the DAGR detects motion at speeds above 0.56 meters per second (default) or an operator-entered value, it uses GPS measurements for azimuth and track determination.

 


How do I know what type of crypto is loaded? I need to confirm if I have a monthly (CV) key, annual (GUV) key, or no key at all.

  • Access the DAGR receiver status display by pushing the STATUS key. You may have to scroll vertically to view all information. The CV LOADED line should display either NONE, GUV, CV, or GUV & CV.

 


What do the CV status messages on the DAGR Crypto Fill Page mean?

  • Go to the DAGR Crypto Fill Page to see status of crypto variable (CV) keys. Click on Status Key/ Receiver Setup Menu.
  • The CV status will display one of these entries:
    • No CV Keys Loaded
    • Have today's CV Key – this means the keys are loaded
    • No CV for Today – could mean either a) a Black GUV is loaded and the receiver is waiting for the daily key to be downloaded after tracking the SVs, or b) there are CVm (monthly) or CVw (weekly) keys loaded, but a key has expired or is not effective.
    • Waiting for SV info - indicates your DAGR has a Group Unique Variable (GUV) key but has not collected enough satellite (SV) data to generate the daily key. The fix here is to leave your DAGR in tracking mode and wait about 15 minutes. Check the display again to see if the receiver has now collected enough data to generate the key (refer to TM para 7.2.2.2)

 


How many maps can I load into my DAGR?

  • The DAGR has 32MB of memory dedicated to maps and images. This will provide you with room to store 3 or 4 one-degree grid squares of 1:50K TOPO maps. This is the type of map you will find at the DAGR maps page on the AGC website. As many as 100 individual map objects can be loaded to DAGR, subject to the 32MB limit.

Can I see other DAGR positions from my DAGR?

  • No, DAGR is just a receiver. It is not a transmitter, so it does not emit signals of any kind and cannot “communicate” with other devices. In practice, FBCB2, Blue Force Tracking, and other Situational Awareness devices utilize a GPS receiver to generate a position location and or time stamp that is used by their device when transmitting within their system network.

Is there a planned M-code replacement for a DAGR?

  • Within the Army, there are a mounted and dismounted solution for replacing DAGR. They are as follows:
    1. Dismounted Assured PNT Systems (DAPS):  The DAPS is the dismounted solution that is marked for use on with the Nett Warrior ensemble. DAPS fielding will begin in the FY 2022 -2023 timeframe.
    2. Mounted Assured PNT Systems (MAPS):  MAPS is a system that has multiple DAGR communication ports, additional sensors to aid the PNT solution, and an Anti-Jam antenna. The MAPS is designed to replace one or multiple DAGRs on a platform. Various versions of MAPS will be fielded in the FY 2022 – 2023 timeframe.
    3. Direct DAGR M-code replacement:  For DAGR users who require a direct DAGR handheld replacement that can be integrated into systems, the GPS Directorate, located at Los Angeles Air Force Base, is procuring the MGUE (Modernized GPS User Equipment) HH (Handheld). MGUE HH solutions may be available in the FY 2027 – 2028.

 


GB-GRAM FAQs


How do we procure GB-GRAMs?

  • GB-GRAMs can be procured through Army PM CHS: usarmy.apg.peo-c3t.mbx.pd-chs-ordering@mail.mil. You may also procure GB-GRAMs directly from BAE Systems.

 


What Interface documents do I need to understand how to integrate the GB-GRAM into my system?

  • Besides the GB-GRAM Performance Specification, the following documents are key to integrating your GB-GRAM:
    • ICD-GPS-153C, IRN 001, GPS UE Interface Control Document for the GPS Standard Serial Interface Protocol of DoD Standard GPS UE Radio Receivers
    • ICD-GPS-153C Integrator’s Guide
    • Small Serial Interface (SSI) GB-GRAM Integrator’s Guide

Is there any software tool I can use to communicate with the GB-GRAM and help to integrate it into our system?

  • Yes. Compliance Tester Software for ICD-GPS-153 (CTS-153) is a government-owned software utility designed to test the compliance of GPS receivers with IS-GPS-153 interfaces. It also allows you to generate messages to the GB-GRAM and monitor and log message traffic from the receiver.

 


What is the most current version of software for the configurations of GB-GRAMs?

  • The versions are as follows
     

SSI GB-GRAM 3.1
NSN 5825-01-513-9225, Rockwell Collins (RC) Part No. 987-1856-032
SW Version 984-2692-006
 
SSI GB-GRAM 3.2 (Type I)
NSN 5824-01-2662-005, RC Part No. 987-1856-023
SW Version 984-2662-006
 
SSI GB-GRAM 3.7 (Type II)
NSN 5824-01-593-7395, RC Part No. 987-9705-001
SW Version 811-2883-005
 

 

I have never seen a Modification Work Order (MWO) for a GB-GRAM with instructions for updating the software. Are instructions available?

  • Yes. Since GB-GRAM is a component, not an end item, PM PNT does not issue a formal MWO. The instructions, files, and reprogramming utility are packaged and available in the Download Library.

 


The World Magnetic Model (WMM) in my GB-GRAM is outdated. Is there a way to update the coefficients?

  • Unlike the DAGR, the GB-GRAM WMM coefficients cannot be updated via the IS-GPS-153 messages. Currently, the only method to update your coefficients is to establish a contract with the vendor (BAE Systems) to do so. However, a new version of GB-GRAM software will be available in FY2021 and will have an updated WMM (WMM 2020-2025).

We want our GB-GRAM to operate as a military GPS receiver, tracking the Precise Position Service (PPS) Signal in Space, not like a commercial GPS receiver using the Standard Position Service (SPS) Signal in Space. How do I obtain the GPS crypto variable keys to do this?

  • The local COMSEC account must request the crypto variable keys from the GPS Controlling Authority (CONAUTH) at USSTRATCOM.  The contact information is as follows:

 
USSTRATCOM/J673
901 SAC Blvd., Suite 2B28
Offutt AFB, NE 68113
Comm: (402) 294-8556, DSN: 271
Fax: (402) 294-0380 not 0390
stratcom.offutt.j67.mbx.satcom-comsec@mail.mil
 


How should we maintain control of GB-GRAMs?

  • Minimum security standards for the protection and use of the GPS PPS equipment and associated COMSEC material is covered in the Committee on National Security Systems, CNSSI-3006, dated February 2018. All GPS PPS equipment must be controlled to preclude unauthorized access, tampering, theft, or loss in accordance with paragraph 21 of CNSSI 3006.

 


What should we do in the event that a GB-GRAM is lost or stolen? 

  • The following paragraphs describe how to report the loss or theft of GPS SAASM receivers and components. References:
    1. CNSSI-3006 (U) Operational Security Doctrine for the NAVSTAR Global Position System (GPS) Precise Positioning Service (PPS) User Segment Equipment User Segment, dated February 2018
    2. CNSSI 4003 (U) Reporting and Evaluating COMSEC Incidents, dated 16 June 2016
  • IAW Reference a, the loss or theft of a keyed or un-keyed SAASM-based receiver, or HAE, must be reported to the GPS Controlling Authority (CONAUTH), USSTRATCOM. The contact information for the GPS CONAUTH is:

USSTRATCOM/J673
901 SAC Blvd., Suite 2B28
Offutt AFB, NE 68113
Comm: (402) 294-8556, DSN: 271
Fax: (402) 294-0380 not 0390
stratcom.offutt.j67.mbx.satcom-comsec@mail.mil

  • IAW Reference b, the loss of a SAASM device or HAE is not reportable as a COMSEC incident under the follow circumstances: incidents involving the loss of unclassified PPS HAE that is not marked "controlled cryptographic item" need not be reported under provisions of CNNSI 4003 but must still be reported to the GPS CONAUTH under the provisions of CNSSI 3006. IAW Reference a, report this loss to the GPS CONAUTH if particulars of the loss or theft did not represent a reportable COMSEC incident under CNNSI 4003. 

 


Can we DEMIL or locally dispose a GB-GRAM we no longer need?

  • No. For security reasons due to the SAASM (Selective Availability/Anti-Spoofing Module) chip installed on the GB-GRAM local disposal or local DEMIL is prohibited. The DEMIL “F” Instructions identifies the authorized organization to DEMIL the GB-GRAMs.

How do I dispose of my “F” condition GB-GRAM?

  • The GB-GRAM must be DEMILed in accordance with the associated DEMIL F Instructions. You can obtain the DEMIL “F” Instructions from the Army TACOM-Unique Logistics Support Applications (TULSA) site. The identifying information is as follows:

 
                                        Code F                   RC PN                            NSN
GB-GRAM 3.1      NIIN 015139225      987-1856-032       5825-01-513-9225
GB-GRAM 3.2      NIIN 015292565      987-1856-023       5825-01-529-2565
GB-GRAM 3.7      NIIN 015937395      987-9705-001       5825-01-593-7395
 


Do I have to replace my GB-GRAMs with M-code cards?

  • No. There is no mandate to replace GB-GRAMs with M-code cards. However, only M-code cards can be procured unless a waiver is in place.

 


How does an Army program apply for a waiver so we can continue to procure GB-GRAMs?

  • If a blanket waiver is not already in place, an individual waiver can be applied for by contacting US Army HQDA ASA(ALT), Department of the Army Systems Coordinator (DASC). Contact us at usarmy.apg.peo-iews.mbx.pd-pnt-support@mail.mil and we will connect you with the correct POC.

 


PLGR FAQs


My organization still uses the PLGR (Precision Lightweight GPS Receiver); what are the current software versions?

  • The most current software version was released in FY 2008, and can be requested by contacting usarmy.apg.peo-iews.mbx.pd-pnt-support@mail.mil. The software version numbers for the PLGR are as follows:

                                           Software Version             RC PN                         NSN
          AN/PSN-11               613-9854-006          822-0077-002       5825-01-374-6643
          AN/PSN-11(V)          613-9868-009          822-0077-103       5825-01-395-3513
 


I lost my PLGR. What do I need to do in order to get a replacement? (Army users)

  • A military GPS receiver is considered a Class VII End Item (sensitive item) and should be handled accordingly. In most cases, a Report of Survey is the appropriate means of determining accountability for a lost GPS receiver. PM PNT is the action office to provide replacements for lost PLGRs. Contact us at usarmy.apg.peo-iews.mbx.pd-pnt-support@mail.mil.

What do I do if my PLGR needs repair?

  • Do not turn your PLGR in for repair. The PLGR is obsolete, and has been coded as “not suitable for operational use.” Because the PLGR is a PPS receiver, it cannot just be discarded. If you have PLGRs, contact us at usarmy.apg.peo-iews.mbx.pd-pnt-support@mail.mil.

How do I get my organization’s PLGRs DEMILed?

  • The PLGR must be DEMILed in accordance with the associated DEMIL F Instructions. Contact us at usarmy.apg.peo-iews.mbx.pd-pnt-support@mail.mil for instructions.