Ashtech Z12 GPS Receiver

© Brooke Clarke 2009

The top is held on by three screws on the left panel and three on the right panel.

The GMT shown: 21:49:14 is correct. SVs 25, 26, 30, 23, 13 & 16 are carrier locked but not phase locked.

Data Port 12mm ID Fischer Connectors Some Z12R receivers have DB-9 connectors and some have Fischer Push-Pull connectors. These are NOT 7 pin Fischer connectors like on the small box Z12.

12 VDC Input 9 mm ID Fischer 3 pin Connector

Ashtech developed a better way to use the encrypted L2 signal.  The prior art was to square L2 and the Ashtech method has a better signal to noise ratio making it superior.  Also this is the receiver you want for carrier phase timing, which as of 2009 is still an experimental development.  So I've wanted one for some time.

Antenna Drive Voltage

The output voltage is 9.7 VDC positive on the center conductor of the Type-N male connector.  This will smoke a 5 Volt antenna like my roof top unit.
Some options:

• Find an antenna rated for L1 and L2 that accepts 10 Volts.  This is the desirable solution if it's a geodetic grade (ground plane or choke ring) antenna.
  
• Use an L1 & L2 antenna with 5 Volt drive through a splitter that provides the drive and a DC blocked port to this receiver.
  GPS Source - carries splitters (and they are on eBay)
  GPSNetworking - carries splitters (and they are on eBay)
• Make an adapter that takes in the +10 volts, regulates it to +5 and bypass the RF from in to out. <not cost effective>
  

The Trimble 4000ST L1 Geodetic, Model 14177.00 antenna runs on 10 Volts, but is an L1  only antenna.

Front Panel Keys

Pressing any one key or pressing the Red C or Red e key and any other key has no effect.  i.e. none of the key presses does anything.  This may be a fault or just some arcane way they figured out to prevent the unknowledgeable from doing harm.

Hold down the ^ (up arrow) while powering up.  Enter YES (the number 8 key) when asked if this is what you want to do.
It now ends up searching for SVs.

Setting External Ref Freq

When the EXT FREQ is set to 0.0 the internal frequency standard is used, i.e. it's not a requirement to use an external standard.
Press 4, then e, then use arrow keys to highlight EXT FREQ, press e, set to 10 MHz, then press 3, Wait for screen to change to Locked, then press e.
If the external reference GPSDO is not locked then the Z12 does not acquire satellites.  Something happened to the Thunderbolt when there was a power glitch.

AeroAntenna Technology AT2775-42 with the Choke Ring comprises the  AT2775-42+CR which has known phase centers for L1 and L2.
Antenna is L1 and L2 runs from 5 to 18 VDC.
For info about the pole and bi-pod see the DAGR page

NGS NOAA - GPS Antenna Calibration

ANTENNA ID        DESCRIPTION                  DATA SOURCE (# OF TESTS) YR/MO/DY
                                                                                
 [north]  [ east]  [  up ]                                   | L1 Offset (mm)
 [90]  [85]  [80]  [75]  [70]  [65]  [60]  [55]  [50]  [45]  | L1 Phase at
 [40]  [35]  [30]  [25]  [20]  [15]  [10]  [ 5]  [ 0]        | Elevation (mm)
 [north]  [ east]  [  up ]                                   | L2 Offset (mm)
 [90]  [85]  [80]  [75]  [70]  [65]  [60]  [55]  [50]  [45]  | L2 Phase at
 [40]  [35]  [30]  [25]  [20]  [15]  [10]  [ 5]  [ 0]        | Elevation (mm)

AERAT2775_42+CR      Marine III +CR adaptor                   NGS (  4) 05/05/31
      -0.1      -2.6      65.7
   0.0   1.2   2.0   2.6   3.0   3.2   3.2   3.1   3.0   2.8
   2.7   2.5   2.5   2.4   2.4   2.5   2.6   0.0   0.0
      -0.1      -0.4      93.6
   0.0  -0.3  -0.4  -0.5  -0.4  -0.4  -0.3  -0.3  -0.3  -0.4
  -0.4  -0.5  -0.6  -0.6  -0.6  -0.5  -0.2   0.0   0.0\

Results

On Page 0 in the linse for STAT, PL1 & PL2 the letters LK (Lock) appear under all the SVs that are visible. 

They are fischer A086, 104 series.   (Plastic)  (Metal)

# of contacts	Contact pin Config	Interface	Metal Plug	Contact Block	Top Shell	Bottom Sheell	Ferrule
3	A040	U1 504-A	S 103 A040+
11	A056	U1 504-A	S 104 A056+
16	A086	U1 504-A	S 104 A086+	E21 504-A086-J (solder) E21 504-A086-K (crimp)	U31 504-A03 (blu) U31 504-A04 (vio) U31 504-A09 (trq)	U32 504-A03 (blu) U32 504-A04 (vio) U32 504-A09 (trq)	U33 504/5.0

0. Find mating connectors.
1. Record receiver data and convert to RINEX format.
TEQC — The Toolkit for GPS/GLONASS/Galileo/SBAS Data -

2. Submit RINEX file to Online Positioning User Service - which uses three CORS sites to reduce data.