DAGR - Defense Advanced GPS Receiver

© Brooke Clarke 2008 - 2014

    Firmware Versions
    GPS Signals
    Major Influences
    DAGR (Polaris Guide)
    GB-GRAM (Polaris Link)
    Classical PVT
    North Finding (Gun Laying System)
    Target Location
    Carrier Phase Data

    Comparing PLGRII and DAGR
    External Antenna Jacks

    J4 External DC Power
       Stock Turck PKG3
       DAGR Specific
    J1 & J2 D-Sub 15 Pin Connectors
        Have Quick & 1 PPS J2 Cable
        Mystery Cable
        Shipping Container
       Azimuth Determination
          Zero Baseline Testing Single Receiver Method
             Survey Equipment
    Time Display
    Operating Modes
    Cold Start
    Maps & Images
Power Splitter
DC Power
Scratches on LCD Plastic
Rockwell Patents
Pruchasing Polaris


The first military use of the GPS system was around 1990 in the desert wars where the SLGR (Trimpack) was used.  It started out as a three channel L1 CA code (i.e. civilian) receiver.  A few years later the PLGR was introduced.  It's a 5 channel L1 receiver that can be used with both the CA and P (when keyed) codes. 

The diagram below shows the evolution of the Rockwell GPS receivers.  I think the PLGR III was an experimental receiver that was not fielded or if it was only in small numbers.

Firmware Versions

as of July 2010
DAGR 3.1
DAGR 3.2
Release Date
Features Added or Improvements
Oct 2004
Original DAGR 3.1
31 Mar 2005
Original DAGR 3.2 w/minor updates to 3.1
31 Jan 2007
Improved under canopy reception, CAS function, better mapping, etc.
27 Mar 2008
Gun-Laying Azimuth function, WMM2005 update, LRF interface functions
30 Mar 2009
Improved multi-path performance, bubber alerts, DAGR-to-DAGR transfer, low battery warning, etc.
Signal processing enhancements for low-power signals, improved Mission Planning in DAGR Map Toolkit, improved data transfer for 'hot start' of other SAASM devices, etc.

GPS Signals

I suspect that a Software Defined Radio type architecture is used.  This means that the DAGR/Polaris can receive the in development L1C, L2C, L5 and M codes with just a firmware upgrade.  Also there are a number of GNSS (Wiki) signals that probably can also be received.

When the receiver is reprogrammed it probably will still have the same number of channels but how they are allocated in frequency and code is TBD.
Link Designation
Freq  (x10.23) MHz Code
1575.42 (154)
Quasi-Zenith Satellite System
Military "
1227.60 (120)
P(Y) IS-GPS-200D
Civilian "

Nuclear Detonation Detection System 1381.05 (135)

being studied for Iono correction
1379.913 (134.888)

Safety of Life 1176.45 (115)
I5  Q5  CNAV

WAAS (Wiki) is for the Americas.  The military WAGE (Wiki) is either global or area specific.  There are similar augmentation systems for other parts of the world.
The L5 signal allows for ionospheric corrections making aircraft (and all other) systems much more accurate.  Another aspect of Safety of Life is signal integrity allowing the user to know he has a good solution and when he doesn't.  WAGE is only available after the GPS crypto key is loaded.

Major Influences

DAGR (Polaris Guide)


The DAGR is the current (accepted 2004, current 2008) receiver.  It's a 12 satellite L1 (12 chan) & L2 (12 chan) receiver that can be crypto keyed. 

It has many improvements when compared to the PLGR.

As of Oct 2008 there are two versions.
AN/PSN-13  p/n 822–1873–001
Firmware: 984-2461-011
AN/PSN-13A  p/n 822-1873-002
The "A" version has a faster serial port to allow the use of USB to serial converters and it has another 1 PPS output.
Firmware: 984-3006-001

The DAGR is procured under specification SS-M/V-600A, SS-M/V-600B, SS-M/V-600C as of 2007.

Polaris Guide HNV-1660
Polaris Guide

PSN-13A DAGR front removed (6 screws)
This receiver does not power up at all. DOA
                  front removed (6 screws)

PSN-13A DAGR Top PCB open (1 screw)
Notice two antennas.
                  Top PCB open (1 screw)

PSN-13A Back Inside
two antennas at top backed by combiner & RF amp has
single coax to mother board.  Other coax is from external ant.
Components on flex circuit are power supply filtering.
PSN-13A Back
PSN-13A Motherboard bottom
RF processing under metal top shields, Lowest metal shield is marked ARM.
                  Motherboard bottom
Near the lower left corner of the big black chip there's a
Honeywell HMC1052 2-axis Hall bridge magnetic sensor.
PSN-13A Motherboard top
Small white socket is for front panel keyboard.
                  Motherboard top

GB-GRAM (Polaris Link)

GB-GRAM In addition to the handheld DAGR there is a 12 Channel printed circuit board version called the Ground Based - GPS Receiver Application Module (GB-GRAM).  Note a Ground Based application will have velocity, acceleration and jerk values much less than those encountered in air and space craft and a GPS can exclude the higher values making for a better solution.    More importantly GPS receivers rated for air or space usage have more ITAR controls on their distribution.

The military DAGR and GB-GRAM are CCI items that can not be sold to civilians, but the Polaris Guide is the civilian version and the Polaris Link is the civilian version of the GB-GRAM.


Classical PVT

The classical military uses for GPS are Position (including waypoints and Routes), Velocity and Time (PVT) and the DAGR has all the capability of the PLGR in this regard.  But in addition it can do more.

Gun Laying System, Civilian: Azimuth Determination

This is listed first since it's the feature that I'm most interested in.
Since both bearing and distance between the two locations is calculated this can be used as a surveying method. 
GLS will shortly be called Azimuth Determination for both the DAGR and Polaris.  This way it's OK for the Polaris to have Azimuth Determination.

Real Time Kinematic (RTK) is the surveying term for a GPS receiver that tracks while it is being moved.  But in the surveying application there's a radio link from the base station to the rover and the actual position of the rover is known.  The North Finding system does not need to know the actual position of either point.

6181274 Satellite navigation receiver for precise relative positioning in real time, MIT, Jan 30, 2001, 342/357.04 ; 342/357.08 - is a similar patent but includes a radio link for code and carrier phase corrections.   The next generation Rockwell GPS receiver may have RTK capability, but it takes more channels since L1 and L2 must be on separate channels.

Single Receiver Method

Using a single DAGR with a survey grade GPS antenna  attached to the top of a pole over a stake and then moving it to another stake you can determine the bearing and distance between the stakes.  This would allow surveying using a single DAGR.  Accuracy of 3 mils (1 mil at 1 km = 1 metre, in NATO countries it's 1/6400 of a circle).  3 MILs is about 10 arc minutes of angle.  Note that the SIN(3 MIL) * base line length is an estimate of the error in the length part of the measurement.  In 100 feet that's about 3.5 inches radius.

The method used is covered in patent 5999123 and involves carrier phase tracking rather than differential corrections.  That's how they get such good accuracy.  Rockwell has a number of patents relating to the detection of carrier phase cycle slip and precision carrier phase tracking methods which would help in this application.  For example excluding some satellites from the beginning if they have carrier phase characteristics that make cycle slip hard to detect.

The accuracy can be improved by minimizing the time of the measurement because many of the error sources change at a slow rate.
The accuracy can be improved by using a long base line.
The above two accuracy improvements work against each other.  The longer the base line the more time it takes to move the receiver.

See zero baseline test results below for the Polaris Guide civilian receiver.

5999123 Time-relative positioning for static applications, Dec 7, 1999, 342/357.08
This is a method based on tracking the carrier phase as a single receiver is moved from one stake to another.  The path between stakes does not need to be along a straight line, but the view to all the satellites being tracked must not be blocked.  It's doesn't work near buildings.
Patent Number Title Issue date
5021792 System for determining direction or attitude using GPS satellite signals Jun 4, 1991
5266958 Direction indicating apparatus and method Nov 30, 1993

Dual Receiver Method (Sub Mil)

xThis provides about the same accuracy as the AG8  gyroscope + Theodolite system but is much more rugged, smaller, lighter and less expensive than the fragile AG8.  But the AG8 does work in underground locations where there is no GPS signal so probably is still being used.

In the dual receiver method you specify a walk time with the two receivers next to each other and cabled together so they can do a precision time sync.  After you have moved the rover to the out post and the walk time expires both receivers make and record a single measurement at the same instant.  Then when the rover GPS is brought back to the master GPS and they are cabled together,  an L1 carrier phase calculation is made to determine the difference between the master and rover locations.  The improvement comes about because both measurements are made at the same time.  In the single receiver method there is a time difference between the measurements.
Accuracy in the 0.5 mil area or around 1 arc minute of angle.

Antennas for Azimuth Determination

They say survey grade external antenna(s) is(are) required for both methods.  Also during the walk between stakes a clear view of the sky must be maintained but the walk does not need to be in a straight line.  The reason for the survey grade antennas is that when a lesser antenna, like the RA-1 is used multipath during the walk causes one or more satellites to break lock making the method non operational.  Survey grade GPS antennas typically have choke rings below the antenna to prevent multipath, but you could mount the RA-1 (or maybe the DAGR/Polaris) over a ground plane to achieve the same result.

Triple Receiver Method?

This is NOT supported on any DAGR as far as I know, but may be on some systems, like on ships.
5021792 System for determining direction or attitude using GPS satellite signals
This is a system that uses three GPS receivers and three antennas. 
Maybe a future enhancement on the dual receiver method, i.e. 3 Receiver method
The antennas are used:
First in a straight line
Second two of them are interchanged
Third one of them is moved away from the line by the distance between the remaining two.
Patent Number Title Issue date
3766556 CHANNEL SWITCHING PHASE - for canceling IF non linearities
Oct 1973
4719469 Direction-determining system - two fast switched antennas and interferometry
Jan 12, 1988
4845502 Direction finding method and apparatus - two antennas on rotating platform are combined in balanced mixer
Jul 4, 1989
4881080 Apparatus for and a method of determining compass headings, Navy - uses two antennas, ant switch and one GPS receiver
Nov 14, 1989

Target Location (Civilian: Way Point Determination)

This was also supported with the PLGR.  By using a compatible Laser Range Finder cabled to the DAGR (or manual input of range, bearing and elevation angle to the target) you can get the coordinates of a target.  This requires that the Laser Range Finder sends at least the magnetic bearing and distance to the target and better in addition the elevation angle.  So far I haven't found LRFs on the open market that have a range of more than about 1 km whereas the military LRFs may be good for 10 km.

An alternate way to get target location would involve taking multiple sightings from a different locations (maybe even from a moving vehicle) where you only know magnetic bearing and elevation angle.  Then triangulate the readings.  Note by using more than two sightings averaging can be used to improve the precision of the target location.  The DAGR does support multiple sightings of the same target.

6064942 Enhanced precision forward observation system and Method, Rockwell Collins, May 16, 2000, 701/213 ; 342/118; 342/357.01; 342/357.06; 342/357.08; 434/1; 701/207 - employs multiple measurements to reduce the CEP
Patent Number Title Issue date
5736960 Atomic clock augmented global positioning system receivers and global positioning system incorporating same Apr 7, 1998
5739786 GPS transfer initialization system Apr 14, 1998
5757316 Attitude determination utilizing an inertial measurement unit and a plurality of satellite transmitters May 26, 1998

Low cost astronomical orientation sensors are available that can tell you the magnetic bearing and elevation angle to any target.  For example the Clestron SkyScout or Mead mySKY.

Laser Range Finders

There are civilian LRFs made for golf and sporting applications with ranges up to about 1 km, most are a few hundred yards.  But there are also civilian LRFs that have long ranges.  Very few have data output that can couple to the DAGR/Polaris Guide.  Note:  The data format is not NEMA, but a proprietary Leica format.
Leica Vector IV
Litton Mark VII - 7.3 x 18 day optics, 4 x 50 image intensifier, Nd:YAG laser, eye-safe 1.57 micron Riegl LASERTAPE FG21 - up to 2500 meters
The military LRFs typically have a max range of about 10 km.
AN/GVS-5 (MX-9838) Nd:YAG 1.06 micron) hand held fielded 1980 - Class 4 Non-Eye Safe, only usable in daytime
AN/PVS-6 Mini Eyesafe Laser Infrared Observation Set (MELIOS), only usable in daytime
MLR 30 - 20 km range, 1.064 microns
MLR 40 - 20 km range, 1.54 microns
LH30 - 80 m to 20 km
LH40C - erbium:glass laser, 1.54 microns, built in compass & inclinometer
Leica Geosystems ZVBA
Brashear LP MLRF 100 - 1.54 microns, mounts on personal weapons
AN/PEQ-21B Common Laser Range Finder (CLRF) - similar in magnification and field of view to the M-22 binoculars, built in compass & inclinometer, GPS interface
AN/AAS-38 Nite Hawk
LRM 2500 CI - 2500 m, built in compass & inclinometer
LRB 25,000 25 km - 1.54 micron eye safe,

Carrier Phase Data

The DAGR supports carrier phase data output.  This is the method used by surveyors to get very high levels of precision.  To use the carrier phase data for surveying you need to convert it into RINEX format and then use post processing software to remove the integer ambugity.  RINEX conversion software is not currently available (Oct 2008).  Also it's not clear of the Polaris Guide (civilian DAGR) supports carrier phase on just L1 or on both frequencies.


Frequency hopping radios need the current date and time accurate to less than a second.  The Polaris supports both Have Quick and SINCGARS time formats.


The PLGR-II was made for Special Operations and some foreign governments (Australia, UK?).   It's a 12 channel L1& L2 receiver.
Montgomery Design page about PLGR and PLGR II.  "MDI worked with Rockwell to adjust the surfaces of their prototype unit, minimizing the potential for cavitation."

There are three versions:
SofTouch Standard green case - 1 meter underwater
Dive Capable black case - 10 meters operational (20 meters survive)
Deep Dive gray case - 24 meters operational (36 meters survive)


The removable battery tray can hold up to 8 AA cells.  There is a menu item for Alkaline or Lithium cells and for 6 or 8 cells. (not sure which 6 to install for this option).
The memory battery is the 3.6 V 1/2 AA just like the DAGR.
After installing the batteries the SV Status page shown ALM AGE: 99 DAYS.  But after more than a half hour later the ALM AGE: drops to 1 DAY when for sattelites are being tracked.

Comparing PLGRII and DAGR

Once any GPS receiver has locked onto one satellite it can then download the almanac data for all the other satellites.   That takes a little less than 15 minutes.  Once that's happened the ALM AGE: will change from some number between 2 and 99 days to 1 day.  Prior to taking these two photos the almanac was made current.  The key difference of the PLGRII is it's heavier and the buttons take much more force to activate, probably both of those differences are because this PLGRII can be operated down 10 meters and stored at a much greater depth in water.  The DAGR is only specified for 1 meter of water.

The PLGRII uses an 8 AA cell battery tray with the option of a 6 AA tray that has an external DC power connector.  If you don't have the optional 6 AA battery tray you can not use external DC power.
                & DAGR Outside
                & DAGR Inside

PLGRII External Antenna Jack

                External Antenna Connector
The PLGRII external antenna connector is a waterproof type.  I expect the mating connector looks just like the plug shown here.  It's 6.17 mm (0.243") O.D.  Now to find out what it is.
This is the same O.D. as the 75 Ohm SMB, but should be 50 Ohms and the SMB male pin does not look to be in the correct location.
DAGR External Antenna Jack
                External Antenna Connector SMA
The DAGR External antenna connector is the very common SMA (3mm).  Notice the nut on the external antenna cable will be recessed into the pocket so you can not tighten it with your fingers.  There is a "Spinner" available for this.  It's a plastic wheel with fingers that snap onto the hex nut.
PLGR II Rechargeable battery Holder p/n 988-3123-003 
made in 2002
holds 6 each AA size rechargeable batteries (the stock battery holder carries 8 AA cells).
There is also an external power connector that will NOT accept the standard PLGR power plug.
                Rechargeable battery Holder p/n 988-3123-003
External Power Connector on PLGR II 6 cell battery holder
The connector appears to have the correct threads for the stock PLGR power plug, BUT the plastic case is too small to clear the threaded nut on the plug.
A laptop power plug will not work again because the plastic is too close to the socket centerline.
It appears to be a design defect.  If you know of a power plug that works let me know about it.
                Power Connector on PLGR II 6 cell battery holder p/n
They both work about the same outdoors and indoors.


Holding down MENU gets you to the Quick Menu page.  Use the arrow keys to select and ENTER to goto that menu.

When in Quick Menu is PAGE is pressed the menus rotate as:
Quick Menu -> Operations Menu -> Setup Menu -> Data Menu -> WPT/RTE Menu -> Calc Menu -> SV Menu -> Apps Menu -> Quick Menu

Setup Menu

Use the arrow keys to select and ENTER to goto that menu.



TheTitle line POS or PRECISE can be selected and CLEAR activated.
Lat, Lon, Elevation, Ground Spped and Track can be initialized.
Pressing PAGE brings up the crypto key input in either Hex or Decimal notation.

KOI-18 Load

Select LOAD then pull tape.
LOAD                       QUIT

Data Menu

Use the arrow keys to select and ENTER to goto that menu.


Help Menu

Note:  to get to the Help menu from the Quick Menu instead of pressing down arrow four times just press up arrow once.

HELP      TAB:[A]
If an arrow key is pressed the focus will jump down into the lower list.
If ENTER is pressed, then up or down arrow the letter after TAB: will increment or decrement and the list will change being centered on the new letter.

Once the correct TAB:Letter has been selected press any arrow key to move the focus to the center of the list of topics.  Now press ENTER and notice that to the left of the current topic an Up and Dn arrows appear.  Now pressing UP or DN arrows scrolls the list.

Waypoint Route Menu

Use the arrow keys to select and ENTER to goto that menu.


Receiver Hardware Status

Pressing PAGE:

Data Transfer

Send To:[com-a] [com-b]
Type:[all] rcvr setup]  [targets]  [submode setup]  [user coord]  [time]  [user dtms]  [units setup]  [sv data]  [mission data]  [all]
SEND               QUIT

Operations Menu

Use the arrow keys to select and ENTER to goto that menu.

Submodes: 1 Foot, 2 Gnd Veh, 3 Para HAHO, 4 Aircraaft, 5 Maritime, 6 Dive, 7 Survey, 8 Spare
ACTIVATE                  QUIT

HSF-CFG History File Configuration

Calculate Menu

Use the arrow keys to select and ENTER to goto that menu.




Requires stored Laser Range Finder data

Applications Menu

Use the arrow keys to select and ENTER to goto that menu.




Targeting Menu


Space Vehicle Menu


Tailored Screen Sequence Page

It depends on the selected submode.



Primary AA Batteries

Polaris (DAGR)
        Primary Main four AA Batteries

All the printing is inside the battery compartment.
Notice that the title: Receiver, Hand Held SPS
The "SPS" means Standard Positioning Service" i.e. the legal to own civilian model.
SPS also appears on the lower right of the front panel.

When installing the AA batteries it's best to lower them into the battery holder while holding level.  If you tip the battery and try to install it one end then the other it's a very tight fit.
Don't forget to put the removing strap unter the cells.

L-91 Lithium 1.5 V Primary NSN: 6135-01-333-6101 - these have more capacity and work at temperature extreams where Alkaline batteries fail.

Memory Backup Battery

Polaris (DAGR)
        Memory Battery

The White dot on the memory battery cover and the white dot on the main battery cover are the vents.  Single bump connector is J1, two bump connector is J2.

Memory battery is 1/2 AA size 3.6 Volt Lithium.  Radio Shack 23-026 aka:
3B26TC, 3B33TC, 3B955TC, 29045, ER3S, G3 ER3STC, LS3,
LS14250 NSN: 6135-01-435-4921
TO4, TL-5101, TL-5101/S, TL5111/S, TL5112, TL5112/S, TL5151

Note there is also a 3.0 Volt Lithium 1/2 AA size battery, but it probably will not last as long.

There is no pull strap for this battery and it's a very tight fit, so a small screwdriver may be needed to get it out.

J4 External DC Power

Polaris (DAGR) GPS receiver with Turck PKG3M6S90S Cable

Polaris (DAGR) GPS
        receiver with Turck PKG3M6S90S Cable

This is the connector the Rockwell documents recomend.
BUT, it is very difficult to install and remove because the stock nut is almost completly surrounded by the recessed pocket so you need strong fingernails to install it.
External Power Consumption vs. Input Voltage


Polaris (DAGR) with DAGR specific Cable

Polaris (DAGR) with
        DAGR specific Cable

This cable was made for the DAGR, but may be very expensive.  The problem is there aree really two nuts, the one shown above is on the cable and another nut is installed over it.  The outer nut is not tight aginst the internal nut so after it's been snugged when you wiggle the outer nut you feel slop.  That may cause someone who has not been properely trained to overtighten and that may lead to a broken plastic case.

The other problem is that the nut makes a ratteling noise when the receiver is shaken.  That might consume a lot of someone's time trying to find where the rattle was located.

J4-1 = Ground = Brown
J4-3 = Positive = Blue
J4-4 = no connection

J1 & J2 D-Sub 15 Pin Connectors

The fifteen contact connector on the DAGR is the same one that's on the PLGR.  Most of the functionally is the same as for the PLGR.  For example the PC cable is the same for either the PLGR or DAGR.  They are not exactly the same, but are very close.  The 15 pin High Density D-Sub connector is the same one used for PC video monitors.  The computer monitor cable has DB-15m connectors on both ends and so will not mate to the DB-15m connectors on the DAGR.  But, an HD15 video extension cable has an HD15F connector on one end.  You can just cut off the HD15M connector to have a ready made cable.

Another problem is that when the DAGR is in the mount there is not much room behind it, so a normal DB-15 connector hood will stick out the back too far to allow the mount to be used.  If you know of a hood that can be installed to the left or right let me know.  The Right Angle type connectors have the angle going up or down which is good, but there still isn't a commercial sideways shell.

Note PLGR J2 is very close to DAGR J2 (although there are small differences).  See the DAGR manual J1: Tbl20-1, J2 Tbl20-2.
Polaris (DAGR) 15
        contact J1 & J2
The Radio Shack 276-1502 is a "15 Position High Density Female D-Sub connector with solder cups that fits the DAGR and PLGR allowing you to make up your own cables.   Jameco 164823 is much lower in cost.

Note one bump over J1 and two bumps over J2.  Seems strange that they didn't put three bumps over J3 and four bumps over J4.

In the photo it's not easy to see all three rows of pins on the connector, but they are very clear on the bottom of the dust boot.

The PLGR used a fifteen contact size D-Sub shell to hold the external antenna coax.  That seemed a waste of space and the DAGR uses a recessed SMA RF connector and two fifteen contact interface connectors.  Each of which can be setup to do various things.

J1 Functions

J2 Functions

TBD port Functions

DAGR/PLGR to/from DAGR/PLGR  data set loading (soon firmware cloning)
Reprogram DAGR firmware

COM Port Protocols

Each COM port can be setup to support:
Inputs: ICD-153, Local Area DGPS, NMEA
Outputs: ICD-153, NMEA

Have Quick & 1 PPS J2 Cable

DAGR Polaris Guide Cable for 1
                Pulse Per Second and Have Quick time code DAGR Polaris Guide Have Quick and 1
                PPS Cable with Mount

This cable has the 1 PPS output on the BNC connector and the Have Quick data on the wire pair.  The 1 PPS can be used as the trigger source for the scope and the have quick data then starts at the trigger point.  BUT, the HP54501A Scope can not display the seconds data because of limitations in the window function.  The problem is that there's a preamble on the Have Quick data that's about 1/4 second long and there's a 20:1 relationship between the main time base speed and the fastest possible window speed.

I think a way around this is to use the SRS DG535 as a delay generator triggered from the 1 PPS on this cable and use it's output to trigger the scope.  Now the scope time base can be set to a rate that will allow a number of samples to occur during each 600 micro second bit time.  The plan is to have just the unit seconds (and maybe part of the tens of seconds bits on the screen and compare to a digital clock that turns over on the UTC second edge. Unfortunately the DAGR/Polaris does NOT change it's seconds time display on the UTC edge, but can be off by up to a second or slightly more so you really don't know the time by just looking at the display.  Seeing the Have Quick data should show that it's very accurate.
Have Quick Test Setup The 1 PPS output from the Polaris Guide feeds the trigger input on the SRS DG535.  The DG535 can be set to create any desired delay, such as 268.8 ms to start of 10s of seconds.  The DG535 output triggers the scope Chan 1.  Have Quick data is on Scope Channel 4.

It's a challenge to get all the software needed for the USB video camera to work. 

Under the scope and above the plywood shelf is the Ultralink WWVB receiver.  That data waveform on the scope has been offset so it's at the very bottom so that the video camera can see the data and the time.
DAGR Polaris Guide to Have Quick
Have Quick Cable p/n 987-5002-001 NSN: 5995-01-5212-680
This cable only works on J2.
DAGR plug marked P2 and has two raised dots.
black Ground
brown Have Quick

PC Cable

                Polaris Guide <-> PC Cable
p/n: 987-5012-001   NSN: 5995-01-5213-198
This cable only works on J2 COM1.
DAGR plug marked P2 and two raised dots.
Three wire interface.
No RTS/CTS like on COM3.
No connections for COM2 RS-422.














1PPS-In_Rtn is the same as COM1_RTN
There is no jumper on the computer DB-9 between 7 and 8 so the computer must have it's serial port set for no hardware handshake.
DAGR Polaris Guide P2 Cable
The P2 Cable has a dog leg or double bend to reduce the distance it sticks out the back to a minimum.  The connector is marked both with two dots and with "P2".  This might be a PC or Have Quick cable.

What are the two brass threaded inserts used for?  Let me know.


                426-01410020 NSN: 6150-01-375-8663 DAGR PLGR Cable

NSN: 6150-01-375-8663
p/n 426-0141-020
This is a 42" long cable to allow connecting two GPS receivers together either DAGRs, PLGRs or a mix.
The cable is symetrical and does not have markings for port 1 or port (the PLGR only had one port) and this cable was made for PLGRs but is also used on the DAGR.
Port 1 Port 2
Port 1
Port 2
1 PPS In 1 PPS In 6
1 PPS Out 1 PPS Out
1 PPS Rtn
1 PPS Out
1 PPS Out 1
1 PPS In
1 PPS In
PPS_O_Rtn 2
1 PPS Rtn
COM 3 Tx
COM 1 Tx
COM 3 Rx COM 1 Rx
COM 3 Rx
COM 1 Rx
COM 3 Tx COM 1 Tx

Mystery Cable

                Mystery Cable
May be the Vehicle Mount Fill Cable.


Shipping Container

Received in double box.  This is the inner box with a very cleaver cardboard fold, it's not shrink wrap, you can remove the Polaris after unfolding.
Polaris (DAGR) Inner
      Shipping Box
In addition to the Polaris there was a two page packing slip.  Order placed 17 Oct 2008 received 14 Jan 2009, pretty close to 3 months.
No batteries or other paperwork is included with the unit.

This is the same box used to ship the DAGR.


Azimuth Determination, North Finding, Survey Mode (mil speak: Gun Laying System)

Once in the AZ Determination page proceed as follows:
4AK = 4 Arrow Keys
Is it better to carry the receiver so the LCD is vertical or should the LCD be level? LCD level both for compass and GPS reception.
Where inside the receiver is the internal antenna located? just above the LCD.

Using a choke ring antenna would prevent multipath and so you would not loose as many satellites.  Once a satellite looses lock it is removed from the solution because after it relocks the cycle count is no longer valid.
17 Apr 2009

Zero Baseline Testing Single Receiver Method

A way to test the accuracy of the azimuth determination system is to NOT move the antenna.  In this case the roof top GPS antenna was used for both the first and second positions.  If the Azimuth Determination procedure is run using a fixed antenna the result should be a distance of zero with an arbitrary angle.  Things that can be varied are the receiver mask angle.  Zero degrees increases the number of SVs but also allows for more multipath errors.  It’s also location dependant.  The walk time is controlled by making the setting greater than the actual time and then pressing ENTER at the desired test time.  Note there is no display in the results that will tell you the actual walk time so there’s a few seconds of error in the estimate of the actual walk time.  The number of SVs can be controlled to a small extent by when the test is run since the satellite configuration changes with a 12 hour cycle.

The Walk Time input for the single receiver method just sets the maximum allowed walk time, so it's best to just use two up arrow presses to set it to 180 seconds.  The actual second measurement is made when  you press ENTER at the second location.  My guess is that when the ENTER is pressed the first time the DAGR starts logging carrier phase data.  When ENTER is pressed the second time the DAGR does the calculations involving processing the logged data.  So the time it takes to process the data depends on the actual walk time and is very close to half that time.  For example if the walk time was 2 minutes it will take 1 minute to process the data.

Plot of Range error in Inches vs. Walk time in Seconds

DAGR GPS Azimuth
          Determination (North Finding, Gun Laying) Error vs. Walk Time
          Single Receiver Method Zero Base Line
What's not shown is the number of SVs used for the solution.  When the test is started there may be 8 to 10 SVs being tracked, but once any of them drop out they can not be used in the solution so it's not uncommon to loose one or two sattelites by the time the test has finished.   Maybe because of the change in number of SVs and/or different DOPs the test results are not easy to nail down, but you can see there's a definate relationship
 between walk time and accuracy.  A very rough rule of thumb might be:
Accuracy (Inches) = Walk Time (Seconds) / 20
For example at 20 seconds the accuracy varies from 1/2 Inch to 2 Inches.
At 60 seconds it varies from slightly more than 2 Inches to slightly more than 5 Inches.
The accuracy seems to get better than the rule of thumb when the walk time exceeds 2 minutes.  I'm not sure of this is real, or not?
The problem with trying to use walk times near 180 seconds is that the DAGR aborts the measurement at 180 seconds instead of making a measurement.  It's impossible to have a walk time of more than about 175 seconds because the pressing of ENTER has some time delay before it stops the test.

So for the single receiver method the possible angle accuracy depends on how quickly you can move the DAGR while not blocking any SVs.  These are just calculations that have not yet been tested.

If normal walking speed is three miles per hour (4 feet per second), then after 180 seconds the baseline would be a little under 800 feet (241 meters).  An error of 9 inches in 792 feet is 0.054 deg (3.26 arc min) or 0.96 Mils.
If a running person traveled at 8 miles per hour (12 feet per second) then at 180 seconds the angle would be 9/25344 or 0.0198 deg or 0.35 Mils.
If a car averaging 30 miles per hour moved the receiver and the test lasted 2 minutes the expected accuracy might be 0.0054 deg or 0.096 Mils.

Survey Equipment to support Single Receiver Azimuth Determination

SECO makes a number of poles used to support either GPS antennas or prisim retro reflectors that are suitable for this application and have some very handy features.  Since minimuzing the walk time is important a system where the antenna is just plugged in rather than locted is important.  Although SECO makes a number of clamps to hold survey data collectors they don't have anything that's DAGR specific so I'm going to try and modify one of their plain pole clamps to allow the stock DAGR mounting bracket to be attached.  (13 April 2009)

Part of Azimuth Determination Setup

DAGR (Polaris
          Guide) Azimuth Determination (Gun Laying System, North
          Finding, Carrier Phase Survey) Part of SetupThe Pole and bipod are standard SECO (Survey Equipment Co) items.  This is a very modular system where all the pole sections have 5/8-11 female threads on both ends.

A friction clamp is holding the DAGR standard mount with a 10-32 screw and flat washer making the connection.  The left mounting hole in the DAGR mount is used so that the back connector area is clear of the pole.

Just below the DAGR there is a circular bubble level (black object to left of pole).

Just below the bubble level is a quick disconnect fitting.  The black pole is attached to the pole above and can be lifted off the lower pole.

The lower pole is fitted with the bipod.  The upper part of both bipod legs has a lever actuated length adjustment to allow easy plumbing of the pole.

Rather than spend a lot to get another of these pole setups, I just got a male quick connect pin with a 5/8-11 female thread to put on top of my existing surveying tripod for the second location.

The pole plus bipod arrangement has an advantage over a tripod in that the distance between the GPS antenna and the mark on the ground is a fixed distance.  That's not the case with a tripod.

This setup breaks down to a much shorter length and fits into a carry bag.

DOP Planning

Yesterday (17 Apr 09) there were 7 satellites being tracked but after moving the receiver 33 paces away and returning to the pole the error message was poor satellite geometry.  So some planning needs to be done before hand to chose a time when the geometry is good.  Trimble has a free program called "Planning" to do this. 
Trimble Planning Software Downloads -
They also have a web page where you can get current GPS data.
GPS Data Resources - Almanac files

Outdoor Zero Base Line Walk

21 Apr 2009 - Choose 11:45 to 12:05 window and tried two walks. 
The first for about 2 minutes resulted in a no solution, poor DOP message.
I'm guessing that if I walk too close to my house some sats are blocked and dropped and the remaining sats don't have a good enough DOP.  So to access some locations the path may need to be curved to keep clear of the house GPS shadow.
The second for about 1 minute resulted in a distance error of about 4 inches.

28 Apr 2009- It's straight forward to modify the  987-5006-001 mount by adding SECO p/n: 103868-005 and the associated 1/8 x 7/16 spring pin and 1/4-20x1/2 cap screw.  Then it plugs into the p/n 5198-052 Pole Clamp and can be adjusted for tilt.  You can just see the spring pin below the quick release pin on the mount that mates with one of the the small holes on the pole clamp.
DAGR (Polaris
          Guide) GPS to Survey Equipment Co Quick Release Pin



When displaying the current position press:
MENU - scroll to Select Op Mode - press ENTER - scroll to Average - press ENTER - when a screen to Do NOT MOVE press ENTER again.  Note just below the longitude display the seconds count will increment once per second until it gets to 32400 (1/2 a day or very close to one orbit of the GPS constilation).


In good weather the difference between repeated averages that are 32400 seconds long is 0.01 arc seconds on lat or long and 1 foot in elevation.


DAGR Polaris Guide GPS
                    Receiver Compass Sights

DAGR Polaris Guide GPS Receiver Compass Sights

There is a raised North arrow just above the center of the display.
The down arrow is a raised button with a bearing fudicial line on
the bottom that acts as the rear sight.

In the upper right of the display is the compass bearing ddd.d.
I find even with the receiver on a table it's difficult to set it to better
than a few tenths of a degree.  The display in the photo shows
000.2 deg

NOTE:  The receiver needs to be held so that the plane of the LCD is
horizontal.  Any tip left, right, front or back will introduce an error
in the compass reading.  Best to use the compass with the receiver
resting on a non ferrous table or in the mount (with the moung horizontal).

The DAGR/Polaris Guide has in built-in magnetic compass.  In addition there's a built in World Magnetic Model which needs as inputs the current date, Lon, Lat and Elevation.  Since this is a GPS receiver that knows all those inputs the local magnetic deviation is known and so you can choose to have the compass display referenced to: Magnetic North, True North or Grid.


It seems that you need to calibrate the compass just prior to using it.  This needs to be done away from metal objects.
MENU, MENU, Display Setup, ENTER, scroll to INTERNAL COMPASS, ENTER, ENTER (highlights a field) scroll to ActiveDisabled and use arrow keys to select ACTIVE, ENTER. Scroll down to Last Calibrated, ENTER, scroll to Select Time Zone, ENTER, scroll to your time zone, ENTER.
ENTER, scroll to CALIBRATE while holding receiver level press ENTER and start rotating so the bearing rotates in a full circle.  Watch the display to see if you get a good cal.


The Compass is in the Navigation Displays menu on the Position page with one press of the scroll down arrow.
Once on the Present Position page press ENTER, then use the arrow keys to highlight the compass display and select the bearing reference (I like True which is something other compass designs can not do).
The receiver needs to be kept level while using the compass, like on a table or surveying post.

Power Consumption

In the DISPLAY SETUP compass menu there's an option for Enable or Disable the compass.  The manual says the receiver draws more power when the compass is on than when it's off.  With external power I'm seeing a 2 ma current savings when the compass is turned off (2 ma * 13 V is 26 mw)

Time Display

The DAGR / Polaris Guide POSition page, when scrolled down, shows the current time and date.  But, the displayed time is often in error by 1 second.  This is in my opinion a bug in the Rockwell Collins firmware.  All my other receivers that display time have the seconds change at the UTC second boundry.  The Trimble Scoutmaster even displays the tenths of a second correctly, see image below.
DAGR Polaris
          Guide GPS receiver showing 1 second time errorThe Polaris Guide (DAGR) is showing the time as 0852:00 but the time is really 0852:01.0 as shown on the Trimble Scoutmaster to the right.

An interisting thing about the Scoutmaster display is that the date is shown as:

WED 06 Sep89

That's off by 1024 weeks, i.e. the GPS week rollover problem.
I wonder what the DAGR/Polaris Guide will show in 20+ years?

Internal Magnetic Compass

The Internal Magnetic Compass does not have tilt compensation.  The compass can be found at <press and hold POS> then <down arrow> to see the compass (you may need to press Enter and arrow keys to highlight the compass, the Enter and activate it since the normal mode is not continous operation).  I found that the first calibration was no longer working by turning in a circle and noting that the display did NOT show the expected 0 to 359.9 deg range but instead showed numbers around 160 degrees plus or minus maybe 30 degrees.  After a simple calibration it was working fine.

To check for tilt:
Face magnetic North (or magnetic South) and tilt up or down about 10 degrees and note the change in reported bearing is only a few degrees.
While holding the receiver level, Face magnetic East (or magnetic West) then tilt up or down about 10 degrees.  This causes about a 10 degree error in the bearing because there is no internal tilt compensation.

Suunto Vector
          compass bubble levelThe Suunto Vector wrist instrument has a bubble level (just above the 7 in 337) on it's face to aid in holding it level.
The small rectangle in the upper left is the barometric pressure history.
"N" for North which is the closest of the three letter compass points.
337 degrees magnetic bearing.
The black bar below the bearing has a band at the right end below COMP for compass mode.
The modes are left to right: Time, Alti, Baro, Comp
3:57 local time.
On the very outer circumference at the top is a single black tick.  Opposite it are three ticks.  These form a North pointing arrow.
The Bezel was set to the local magnetic devation years ago and you will see that the North Arrow is pointing very close to the "N" on the bezel.   So the line from 6:00 to 12:00 is pointing close to True North.

See: Experiment Relating to the Vertical Component of the Earth's Field for a similar experiment to that above for the Polaris/DAGR.

Operating Modes

When MENU is pressed (from any of the Position pages) one of the choices is Select Op Mode.  The choices are:
Continuous -a new fix each second
Standby - no satellite tracking to conservi battery power, but data input and all other operations can be done
Fix - get a single fix then go into Standby
Average -
In average mode the Present Position page shows Averaging nnnnn under the L/L info, but the max number of averages is limited to 32400 seconds, i.e. 9 hours.  Seems strange that it's not one orbital period of a GPS satellite or longer.  For example after 32400 averages on my house antenna the position was:
Surveyed Position
39:11:24.5833 N
123:09:50.4842 W
39:11:24.63    N
123:09:50.51     W
Delta (7.3 feet)

Time Only - all the effort is put into getting the time BUT in any mode the time display can be off by 1 second.  i.e. you don't  know the time to a second.

Cold Start

When the Polaris Guide (DAGR) is powered up with an external antenna it takes 30 seconds to lock on 4 or more satellites.  Immediately after the Satellite display shows that almanac is 29 days old.  It may be that with an older almanac it would take longer.

I think the PLGR-PLGR cable can be used to bootstrap a cold DAGR/PG from one that's currently tracking satellites.  This includes position date and precision time.

Maps & Images

The DAGR & Polaris can make use of .gpm map files and .??? images files.  The map can be zoomed in or out.
The civilian map loader is Rockwell p/n 811-1213-006.
ESRI has a number of mapping products that may be related.
The USGS has free maps for download in the store.  For Ukiah they have the 7.5 minute, 30 minute and 1x2 degree maps.
The county planning office has a GIS system and has made custom paper maps for me.  It may be that case that they can also make a custom electronic map that can be loaded into the Polaris?

GPS Map Toolkit Software
The Toolket includes both the Map Creator and Map Loader.
July 2009 -xxx is -006. Price for the Polaris is $751 but I think also requires a multi thousand dollar ESRI GIS software pcakage in order to use it.

To use the Map Creator the PC also needs:
Commercial Joint Mapping Toolkit (C/JMTK) ArcObjects software
National Geospatial-Intelligence Agency  (NGA) map data
Support of raster maps: Compressed Arc Digitized Raster Graphics CADRG) and
                                        Controlled Image Base in C/JMTK

The map capacity of the DAGR is limited to 32 MB max and 100 items max.  Each item can have up to 16 characters in it's name.
Raster maps are used with the image viewer and vector maps with the situational awareness window.
Maps can be loaded from a PC to the DAGR/Polaris, between two receivers, or from the receiver to the PC.


                  Mounting Bracket
                  Mounting Bracket 1/2" Spacer
Mounting Bracket
The spring loaded pins will stay retracted if rotated.
marked p/n: 907-5006-001
Strange that there's no provision for a padlock.
Mounting Bracket Adapter
This adapter bracket has the same four hole pattern as the
plastic PLGR mount.  So by using this bracket you
can mount a DAGR in the same holes that held a PLGR.
The top center hole was made by a prior user.
 marked p/n:  987-5177-001
may also be: p/n 987-5007-001

Polaris in
                DAGR mount
Polaris in military DAGR mount
The threaded hole at the bottom center is for a ground connection.

DAGR Locking Mount p/n: 987-5019-100
DAGR Locking Mount p/n:



The internal patch antenna is at the top facing up so the receiver should be laying flat so the antenna can see the sky.


In order to detect the external antenna and not cause an antenna fault warning message it needs to draw 15 to 60 ma from the nominal 3.3 Volt supply.
3.3 V / 15 mA = 220 Ohms max to 3.3 V / 60 mA = 55 Ohms min.

Trimble 28367-40

                28367-40 L1 GPS antenna

Seems to work OK.  It has an SMA connector mag mount.

Trimble 17572-100 16240-00

                Guide (DAGR) & Trimble 17572-100 Antenna

This is a survey grade antenna with  5/8-11 threads.

A couple of tie-wraps holding the DAGR mounting bracket to the threaded rod.
L1 or L1/L2?

Works well at about 37 mA.

AeroAntenna Technology AT575-75AW-TNCF-000-RG-36-NM

Polaris Guide (DAGR)
                    & AeroAnt AT575
This is a survey grade antenna with North Arrow and 5/8-11 threads.

The threaded rod is rrequired since the TNC connector on the antenna would otherwise hit the black tripod adpter.
Frequency: 1575 +/- 5MHz(L1)+ Glonass
Polarization: Right Hand Circular
Axial Ratio: 3 db max
Gain: 00,12dB,26dB,36dB
Voltage: 00,05,RG(5-18VDC)
Impedence: 50 OHMs
VSWR: <=2.0:1
Magnet: NM(No)
Finish: Weatherable Polymer
Color: W,O
Weight:13 oz max.
AeroAntenna Technology AT2775-42 with the Choke Ring
                Technology AT2775-42 with the Choke Ring
Now being used with Ashtech Z12R GPS receiver, but probably will work with DAGR.  It should be the best antenna so far for North Finding because of the choke ring lowering multipath fading.
                Technology AT2775-42 with the Choke Ring

Sensor Systems S67-1575-58

                Guide (DAGR) with Sensor Systems S67-1575-58
This is a passive antenna, i.e. no gain and is a DC short circuit.  The Polaris Guide protests:

This is caused by the DC shorted nature of the antenna.  You can see in the photo at left that the Polaris Guide (DAGR) is working fine with a passive antenna.  All that's needed is a series resistor choonen to present the minimum acceptable power consumption to make the receiver happy and allow the passive antenna to be used.

Garmin GPSIII Plus Antenna

This is a DC open antenna so the receiver does not know it has an external antenna attached.  Tried to fool the receiver by pointing it up and covering the top with my hand while not coverning the external antenna, but this caussed a jamming warning message.  A DC load would needs to be added to try it.
Lucent GPS
                Quad-Helix GPS Antenna KS24019L112C
Lucent Quad-Helix GPS Antenna KS24019L112C

5" tall x 3 1/8" dia.
Type-N male connector
4 helicoil inserts in ____" square pattern.

26 dB gain at ______ to _____ DCV.
Lucent GPS
                Quad-Helix GPS Antenna KS24019L112C
The RF amp is below the ground plane plate.
With a Fluke 87V DMM in diode mode the
antenna Vf (1 ma) reads 1.65 V.
RA-1 Magnetic Mount Remote Antenna
p/n: 13499-013-1981-010, NSN: 5985-01-502-6692
Commercial model:  AT2775-1030-SMAF-000-03-26-IM
DAGR RA-1 GPS Magnetic Mount Antenna p/n:
                          13499-013-1981-010, NSN: 5985-01-502-6692 DAGR RA-1 GPS Magnetic Mount Antenna p/n:
                          13499-013-1981-010, NSN: 5985-01-502-6692
DC Checks:
Fluke 87V DMM -

0.897 V
0.567 V
0.648 M
346.7 k

DAGR antenna cables for the RA-1 are:
When the voltage gets to 2.6 V or higher the current
limits to 35 ma.  Only tested up to 5 V but may work with higher inputs???? Let me know if you know the upper limit.


DAGR to RA-1 Cable (5m with SMA connector), p/n: 13499-987-4640-001, NSN: 5995-01-504-1762
DAGR to RA-1 Cable (5m with SMA
                          connector), p/n: 13499-987-4640-001, NSN:
DAGR to RA-1 Cable (5m with SMA
                          connector), p/n: 13499-987-4640-001, NSN:
DAGR J3 Antenna SMAf
                          GPS + RA-1 Antenna & 5 meter cable
DAGR with RA-1 and 5m cable
                          GPS + RA-1 Antenna & 5 meter cable

                  to RA-1 Cable (5m with SMA connector), p/n:
                  13499-987-4640-001, NSN: 5995-01-504-1762


Name of manufacturer who makes this SMA thumb whee "Spinner".  Let me know.

DAGR to RA-1 Cable (10m with SMA connector), p/n: 13499-987-5016-001, NSN: 5995-01-521-4244

DAGR to Helmet Antenna Cable, p/n: 13499-987-7002-001, NSN: 5995-01-521-6753

SMA DAGR Spinner
p/n: 13499-988-9389-001, NSN: 5935-01-534-6963
Name of manufacturer who makes this SMA thumb whee "Spinner".  Let me know.

Commercial SMA Wrenches that fit into DAGR Antenna connector hole.  But these are tools that will be something seperated from the DAGR and can easily get lost.  The plastic thumb wheel is compact and attached to the DAGR.
KCR Products - Combined with torque wrench, patent US7080581
Mini-Circuits: without torque wrench (but about same cost) HT-2-SMA

Power Splitter

When the Polaris Guide is getting it's antenna input from a power splitter, like the HP 58535A
HP 58535A 2-way
        amplified GPS splitter
The display shows:
Communication Lost.
Check Cable, Power
and COM Settings
ENTER to Acknowledge
Note: this is different from the open antenna error.

The voltage at the antenna connector (J3) is 3.280 V when there's nothing connected.
When a 330 Ohm resistor is shunted across the antenna coax the voltage drops to 3.165 V for a current of 9.6 ma.  This turns off the ANTI-JAM warning.
Polaris Guide (DAGR) ANTI-JAM
Polaris Guide (DAGR) ANTI-JAM
                message Fixed

DC Power

The DAGR uses a three terminal power connector, different from the PLGR's commercial type coaxial two terminal connector.
DAGR External Power

DAGR External Power
          CableThe connector is made by TURCK and the manual says is in their PKG 3M-6 series.  But that connector will not work.  The problem is that the DAGR J4 connector is recessed into a pocket, like the J3 RF connector, and so you can not grab the kunrled part of the nut as shown in the photo at left.

Turck will sell a raw connector, but they are priced about 4X higher than a connector assembled onto a cable like the one shown at left.

There are at least three versions of the connector applicable to the DAGR:

Scratches on LCD Plastic

Tried Meguiar's 17 Clear Plastic Cleaner - but it's only for "fine scratches".  it polished the plastic but did not remove the scratches.

LCD Scratches in Plastic Polaris
                Guide DAGR
This is what the screen looked like after the Meguiar's.

Next will use Novus #3 Heavy Scratch Remover by hand first, then if necessary using a buffing wheel on a drill press.

Rockwell Patents

In addition to the patents listed here Rockwell has many many more.  They are heavily into all parts of GPS including satellites and aircraft systems in addition to the ground units that are the focus of this web page.  In addition they have patents that make use of GPS for things like factory automation.

7142159 Pseudolite navigation system, Nov 28, 2006, 342/386 ; 342/357.02; 342/357.06; 455/13.2 -
Uses communication satellites with custom up and down link signal formats to get around jamming or poor visibility
7230999 Method for extended coherent data demodulation for GPS receivers, Jun 12, 2007, 375/316; 375/340; 701/213; 701/214; 701/215; 329/304 -
Uses two I&Q signals offset in time and then differenced.
7190746 Multiple lobe dot product detector for M-code GPS receivers,
6973150 Cycle slip detection using low pass filtering, Dec 6, 2005, 375/371; 375/376 -
Works with single antenna systems.
6959057 Method of enhancing signal tracking in global positioning system receivers
Instead of using a FFT method of searching for the signal frequency, a filter bank is used which is faster and more robust
6738015 Vector extended range correlation tracking of global positioning system (GPS ...
A Kalman filter uses pseudorange errors to calculate position and velocity corrections in order to better process weak signal code tracking
6687316 High resolution correlator technique for spread spectrum ranging system code ...
Multipath mitigation by using three high resolution correlators, one early, one on time, and one late allowing interpolation
6683867 Parallel precise time transfer to multiple GPS units
Often GPS receivers are turned off prior to a mission to conserve battery power.  Then just prior to commencing the mission are powered up and loaded with precision time and position data from a receiver that's been kept hot.  When there are many receivers that are off this patent teaches combining the 1 PPS with the serial data onto a single data line.
6647080 Carrier phase initialization with sub-LSB accuracy
A method of computing the command word to an NCO to get sub-LSB accuracy
6636558 Multipath mitigation approach for spread spectrum ranging/positioning systems
Multipath is detected as slope differences prior to and after the correlator peak
6590528 Low cost interference reduction system for GPS receivers
Multiple antenna system in front of GPS receiver
6570531 Satellite navigation receiver designed for compatibility with aircraft automatic landing systems
An attempt to recognize failures by comparing two GPS solutions
6556167 Direct acquisition of very large PN sequences in GPS systems
Direct acquisition of the P(Y) sequence without the Hand Over Word from the L1 C/A code by breaking up the P(Y) code into a number of sub sequences and testing all of them.  Instead 15000 sub sequences that have gaps between them are repeatedly tested thus covering the gaps.  320 seconds should be enough time to search the full weekk of code.  This is an important capability for cases where the L1 C/A code is not available, like when it's being jammed.
6501424 Use of GPS correction data on trans-oceanic route
HF radio is used to send the airplane differential corrections like are now sent to coastal ships using LF radio
6421006 GPS augmentation using time offset code modulation
By offsetting the PN code by a large amount (hours) relative to the actual GPS time pseudolites will not interfer with normal GPS operation
6393291 Method and apparatus for deriving a high rate output in a GPS system
Combines kinematic and differential corrections to achieve high rate precision corrections
6388611 Method and system for dynamic surveillance of a remote object using GPS
Combines GPS and TV image to determine target coordinates
6369752 Direct acquistion of very large PN sequences in GPS systems
see 6556167 above
6359585 Apparatus and method of determining an orientation of a GPS receiver
Based on using a directional antenna in the GPS receiver either in max signal or null methods.
6336076 Long range GNSS ephemeris data transfer method and apparatus using the same
Pseudolites are sued to transfer ephemeris data - maybe when the L1 C/A code is not available/jammed
6336061 System and method for attitude determination in global positioning systems (GPS)
Uses two receiver - antenna units
6311127 Satellite navigation system having redundant signal processing and matched ...
Aimed at aircraft systems that need to know if they are not working
6307514 Method and system for guiding an artillery shell
Uses a four segment antenna that can be electronically steered
6297769 System and method to estimate carrier signal in global positioning systems (GPS)
A dual receiver approach to attitude determination
6272174 Multiple frequency bin processing
see 6959057 above
6266009 Method to improve carrier smoothing of code pseudorange for global positioning and GNSS receiver implementing the same
By using dual frequency carrier phase methods the ionospheric variability is reduced
6259400 Fast acquisition of GPS signal corrupted by doppler or time delay effects
Artillery shell converts GPS to another frequency which is reconverted back to GPS at a base station.
6256583 GPS attitude determination system and method using optimal search space ...
Optimized integer ambiguity searching
6208289 System and method for monitoring and reporting GPS pseudo range correction data
A second fixed GPS receiver is used to test differential correction data before it's sent to mobile units
6204806 Method of enhancing receiver autonomous GPS navigation integrity monitoring ...
For aircraft fault finding
6198430 Enhanced differential GNSS carrier-smoothed code processing using dual ...
Dual GPS frequency differential corrections
6188353 Interbuilding and urban canyon extension solution for global positioning systems
Concept for a second positioning system powered by utility lighting
6166683 System and method for high-integrity detection and correction of cycle slip ...Dec 26, 2000, 342/357.04 ; 342/357.11
Excludes satellites where a cycle slip would be hard to detect and uses the delta phase from two antennas to  detect a slip
6163021 Navigation system for spinning projectiles
Magnetic sensor used to generate a despun reference frame for an INS system and GPS receiver
6098547 Artillery fuse circumferential slot antenna for positioning and telemetry
see 6307514 above
6069585 Personal direction finding apparatus,May 30, 2000,  France
342/443 ; 340/979; 342/147; 342/195; 342/29; 342/417; 342/450; 342/454; 342/455; 367/107; 367/116; 367/124; 367/125; 367/126; 367/99; 381/300; 381/309
Stereo headphones provide an audiable signal to maintain a given magnetic bearing
6067503 Method and apparatus for compensating unexpected frequency shifts in positioning receivers
Method to overcome the launch high G shock that can break lock of GPS receiver in artillery shell
6064942 Enhanced precision forward observation system and method
See Target Location above
6020854 Artillery fuse antenna for positioning and telemetry
Design compatible with the above GPS and telemetry antennas
6018314 Method for obtaining PPS accuracy using an unclassified GPS receiver ...
About limiting the security boundry inside a GPS receiver to lower it's cost
6016121 Multiple frequency GPS receive operation using single frequency sequencing

5990831 FFT implementation of digital antenna arry processing in GNSS receivers
5 more?
5990826 Interbuilding and urban canyon extension solution for global positioning systems
5943008 Single global positioning system receiver capable of attitude determination
5940027 High accuracy low power GPS time source
Time of day clock for GPS receiver (why better than the DS32khz?)
5903654 Method and apparatus for eliminating ionospheric delay error in global ...
5886665 GNSS local constellation/acquisition aiding system
5883597 Frequency translation method and circuit for use in GPS antenna electronics
5883596 ?
5883595 Method and apparatus for mitigating multipath effects and smoothing ...
5748136 Electronic landmark enhancement to GPS based navigation systems
5742207 Tracking loop having instantaneous frequency shift protection
5606732 Direct connect radio and antenna assembly
5552794 Position estimation using satellite range rate measurements
5495408 Method and apparatus for signal tracking using feedback control loop
5488378 Method and apparatus for determining positions on the earth corresponding to an observed rate of change of satellite range
Cold start position improvement by using the first pseudorange and doppler shift
5403197 Antenna extender apparatus
Looks like the PLGR antenna
5249027 Inter-vehicle distance measuring system
Not GPS, but based on IR between vehicles on digital highway
5202693 GPS signal processing with 5-level carrier injection demodulation function ...
5021792 System for determining direction or attitude using GPS satellite signals
"A system for determining spatial orientation based on the carrier phase of signals received from a set of GPS satellites. The system comprises an antenna array including a number of antennas coupled to GPS radio receivers, a mechanism for reconfiguring the positions of the antennas within the array and a signal processing module for processing the data collected by the antennas and the receivers. The mechanism for reconfiguring the antenna array is adapted for exchanging the positions of one pair of antennas and for rearranging the antennas from collinear into non-collinear patterns. Phase measurements are taken by the antennas and their associated receivers, both before and after antenna exchange and after antenna rearrangement in order to provide the data necessary to determine direction or attitude."

This may be the method used in the dual receiver GLS.

4910525 Audio verification system and technique for GPS receivers, Mar 20, 1990, 342/418 ; 342/356 -
Rockwell has a patent on making the Doppler shift from a selected SV into an audio signal.
but based on the issue date doubt this is currently being offered. 

Pruchasing Polaris

Starting Sep 13, 2008 I am trying to pruchase one or more Polaris receivers.  Which ones and what accessories depend on the quote.  On 14 Oct 2008 I learned that a number of the items that I have asked for quotation are non standard and must be priced which can take up to a month.

My current thought is to get the Polaris Guide and accessories for a single receiver North Finding system, except instead of getting it's case get the case for the dual receiver North Finding System to that it would be easy to expand to that system.  The operational difference between the single and dual receiver systems is not yet known, but has been requested.

The long process was expected since when purchasing a battery adapter for the PLGR a similar thing happened.  It took a very long time to buy a simple part.  I think this is because they are setup to sell to the U.S. Government and need a lot of paper work to do that so do poorly when trying to sell a simple item.

Glossary, GPS

MPE Minature PLGR Engine
WAAS (Wiki) Wide Area Augmentation System promoted by the FAA, geostationary satellites transmit GPS corrections similar to RTCM-104 differential corrections
WAGE (Wiki) Wide Area GPS Enhancement, military version of WAAS (< 4 meters)
GB-GRAM Ground Based - Gps Receiver Application Module uses the same SAASM
ICD-GPS-060 Have Quick
ICD-GPS-153 Programming serial Interface includes both hardware and commands
ICD-GPS-200 Signal from satellites
SINCGARS - Single Channel Ground and Airborne Radio System, frequency hopping mode needs Time Of Day and date
Have Quick (Wiki) (SS110990) - Frequency hopping mode needs Time Of Day and date
NMEA 0183 (Wiki) National Marine Electronics Association spec for serial data messages to allow interoperation of instruments 4800 baud, limited capability
RTCM-104 (Wiki)
DS101 (Wiki: Fill Device)
DS102 (Wiki: Fill Device)
SPS (<100 meters)
PLGR Precise Time (SS-M/V-500)
TOD Time Of Day
GPS Global Positioning System (Wiki has a good treatment)


Rockwell Collins - DAGR - Polaris Guide - GB-GRAM - Polaris Link -
U.S. Army Product Manager, GPS -
Space and Naval Warfare Systems Command (SPAWAR) - GPS & Nav Systems -
Wiki: GPSGPS Modernization - GPS Signals - Wide Area Augmentation System (WAAS) -
Talon NAMATH, Link 16(Wiki), ZOAD, SBIR, and Other (GPS) Code Words - GBU-39 (Wiki)
Orbit Determination and Satellite Navigation
    - Sensor Systems for Satellite Tracking
    - Precision Modeling for Orbit Determination -
    - The Kalman Filter: Applying the Scientific Method
    - Tracking Geosynchronous Satellites with GPS
Air Force Space Command - High Frontier Vol 3 Nbr 2 "Global Positioning System International Challenges and Opportunities in the 21st Century"
Caltrans -Surveys Manual - Ch 4 Survey Datums -easy to understand explanation about how NAD83 differes from NAD27 - Ch 9 Control Surveys -
GPS Explorer - a page to locate GPS reference stations and geodetic markeres

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