The problem is that this receiver used a very special antenna that needs both a DC and reference frequency input on the coax connector and contains a mixer so that the signal send down the coax is much lower in frequency than the GPS L1 frequency. This is great for allowing long coax run length with low losses, but since these antennas are about a common as hen's teeth it's a problem for getting the receiver to work. One idea is to see if the incoming coax signal is converted to some other IF signal which might be an injection point for a more easily generated frequency.
"Timing GPS Receiver. Fixed Price subcontract from Quantic Industries (under Prime Contract No. F04701-92-C-0067 from U.S. Air Force Space and Missile Systems Center, Los Angeles AFB, California). I3C teamed with Quantic Industries and Stellar Navigation to design, develop and support a Timing GPS Receiver to replace all LORAN-C receivers worldwide in the Defense Satellite Communications System. I3C's responsibilities included total management of all ILS requirements for the multi-service program."
The construction is heavy on the EMC/EMI Tempest side with a lot of shielding of all ports including the fan input and output.
There are 4 major electrical parts:
- Power supply board on left
At the front the Brown + Blue cable is the 120 VAC 60 Hz mains input
The Red + Green cable is the DC power input
The White + Black cable is from the 115/230 VAC switch
There is no on/off switch, once powered the receiver is always running.
Black, Red, White, Blue and Gray wires go to the front panel PCB.
Black, Red, Brown, Yellow, Green and Blue wires go to the Receiver board
- Front panel display printed circuit board includes the LCD has ribbon cable to the keypad.
- Input/Output board connected to rear panel : 1 PPS & 1/5 MHz in; 1 PPS, 1 MHz, 5 MHz, 10 MHz out
has a Piezo 2900082-45 10.000 MHz Oven type oscillator
There is also a Raltron 44.456 MHz DIP type oscillator
- "Stellar" "GPS Clock Module-TTFM CCA"
The unmarked metal can on the top contains an MC1648L 1 to 100 MHz VCO, 78L05 +5 VDC regulator, L10 an adjustable inductor, MCL TI-IT transformer. Near the Piezo ovenized 10.000 MHz oscillator is a Raltron 44.456 MHz oscillator in a can. The 44 pin IC near the center of the board is an STEL-1173/CM, NCO used as a D/A converter as described in the patent referenced below. Adjacent to the MC1648 VCO there is an area of the PCB with 11 DIP ICs that has a ground trace surrounding the circuit.
The MECL 10H parts this area are:
U38, U51, U58 = MC10H131 - Dual D Type Master-Slave Flip-Flop, up to 250 MHz toggle frequency
U42 = MC10H136 - 4 stage counter up to 250 MHz
U53 = MC10H116 - Triple line receiver
U37 = MC10H174 - Dual 4 to 1 Multiplexer
U7 = MC10H103 - Quad 2-Input OR Gate
U39, U43 = MC10H125 - Quad ECL to TTL Translator
U36, U48 = MC10H124 - Quad TTL-to-MECL Translator
By dividing down an oscillator running at 100 or 200 MHz steps of 10 pico seconds can be made.
The can for 10 MHz out contains an MCL314 transformer and passive R, C and L chips.
Between the 1 MHz out and the 1 PPS out there are 3 each 74AC163 100 MHz Synchronous Presettable Binary Counters (count from 15 to 0 & can be preset)
- Receiver Board - Stellar GPS Digital CCA s/n 00213
Receiver board under the I/O board: RS-232, CR & PWR Alarms, CR CTRL and ANTENNA UNIT rear panel connectors a ribbon cable connects to the front panel PCB and a separate set of wires connects to the KEY LOAD 6-pin connector. Brown + Purple wires go to the rear panel backup battery holder. There are 2 each 40-pin connectors between the receiver board and the I/O board (80 total interconnect pins). Some of the big chips are:
- U3 & U4 = L1A3433, STEL-9560, Coderlater, SAE 9315 68 pin quad pkg - Stanford Telecom L1 frequency DSP receiver ? # channels
- U35 = STEL-9300 - maybe a windowed EEPROM with the code for the L1A3433 chips 40 pin DIP
- U9 = 80286 CPU
- U15 = Stellar GPS Corporation, Ver 1.6 900212 c1994, 500-00004-01 - maybe the ROM for the 80286 - 40 pin DIP
- U24 & U25 = Sony, CXK581001M-70L - maybe RAM chips for the CPU
- U18 - has paper label, 20 pins, ?
- JP1 - 34 pin - ribbon cable to front panel
- J8 - 2 wires to backup battery on rear panel
- J9 - 5 wires, red & black to front panel LCD board, 5 wires (brn, blk, grn, blu, red) to KEY LOAD jack on front panel.
- J6 -14 pins RS-232 on rear panel
- J5 - 12 pins CR & PWR ALARMS and CR CTRL on rear panel
- J4 - 6 pins Molex from power supply
- SMA female to ANT on rear panel
- J1 & J2 - each a 40 pin socket going to the Clock board above the receiver board.
The Q5200 sends both +15 Vdc power and a 11.114 MHz reference frequency up the cable to the Antenna Module. The Antenna Module receives the satellite L1 frequency and down converts the signal to an IF of 153.028 MHz which is sent down the cable to the receiver.
This is a 6 channel receiver. I think each STEL chip can handle 3 channels and there are two chips.
So far it looks like the Antenna Module is not a single mixer, maybe is a double conversion scheme.
Maybe the AN/CYZ-10 Data Transfer Device (DTD) could be used to load GPS keys into the Q5200?
In order to get power to the unit I needed to replace the line fuse holder because the cap was missing and the new fuse holder cap did not work.
Now the fan runs and the front panel 2 row by 40 coul. LCD backlight comes on and the display is all 5x7 dot patterns.
The power supply outputs are:
Wire Color Voltage
White .750 open Yel & Blue +15.0 1500 Black -.020 0.2 Gray & Brown -.020 0.2 Black -.031 0.2 Red 4.97 102 Red 4.97 102 Green .095 0.4 Blue -5.13 938
The AC Power and Loss of GPS LEDs light constantly and the Key Accepted and Key Rejected LEDs blink in unison.
After removing the GPS and Clock boards to take the above photos and reassembling the receiver, it now is working .
See Hints & Tips for why this happened.
The Display now shows the power up screen: Quantic/Stellar Timing GPS Receiver, 6 Jan 80 (power up date) 00:00:54 (clock that started at power up), Version 1.6 19 SEP 94 (date of version 1.6), Fault AB00.
Pressing ESC on the keypad brings up the Main menu screen:
- 1 Configuration
- 1. Configuration Menu
- 1) Lockout - panel lockout
- 2) El Mask - 0 to 90 deg
- 3) Bias Cal - set delays for Antenna, cable and receiver in ns
- 4) Freq Ref - Internal or External
- 5) Time Ref - GPS or UTC
- 6) RS-232 - Baud (1200, 2400, 9600, 19200), Data Bits (7, 8), Modem (Yes, No), Parity (None, Odd, Even), Stop Bits (1, 2), Msg Rate (0 to 999) ?
- 7) Panel - Locked or Unlocked
- 8) Meas - Measurement (No, Time, Freq
- 9) Log - Log Status ?
- 2 Operation
- 2. Operation Menu
- 1) Receiver Mode - Static positioning, Time Transfer with Location, Time Transfer
- 2) Mission Duration - will not accept today's date
- 3) Zeroize - clear the Key
- 4) Clear NVRAM - ?
- 3 Review
- 3. Review Menu
- 1) Status - displays: date & time, "data invalid", Tracking 0 SVs, GPS DB Incomplete, Fault AB00
- 2) Position - date & time, LAT = N 0:00:00.00, HGT = 0m, LON = 0:00:00.00, PFOM = 0
- 3) Velocity - date & time, Speed = 0 m/s, Heading = 0 deg, Uncertainty = 0 m/s
- 4) SV Tracking - date & time, Channel (1), PRN=0, C/N0= 0 dBHz, El=0, Az=0, DOP=0Hz (6 channels using arrow key)
- 5) GPS Database - incomplete
- 6) SA Status - date & time, AUTH NO KEY, KEY NA, MD NA, 0 hrs
- 7) TFG - TaF Generator, data & time, Time = 0 ns, GTFOM = 9
- 8) TFM - TaF Measurement, date & time
They do not return email and their phone and fax numbers are out of service. Maybe out of business, but the web page is still alive?
Terry Osterdock Jr is the contact for the absolutetime.com URL.
- Global Positioning System (GPS) in the Defense Communications System (DCS) Proceedings of 1993 IEEE June 2-4 1993 pp 40-44
- Model 300 (about same as 5200?)
- Using a new GPS Frequency Reference in Frequency Reference Operations -
US Patent 5440313 - One of the neat things this patent covers is the idea of using the carry out of an NCO which is integrated in a low pass filter to form a 48 bit D/A converter. You can not buy D/A converters with this many bits. Also instead of jamming a change into the 1 PPS timing they lock the 10 MHz internal oscillator to the GPS 1 PPS resulting in slower changes. There is a provision for an external standard input that's trimmed by the GPS 1 PPS and if the GPS fails the external standard is still trimmed by the last valid amount.
990 Commercial Street, San Carlos, CA 94070-4084
They are still in business, but have sold off this product line to Absolute Time.
STELLAR GPS CORPORATION
800 Charcot Avenue, Suite 110, San Jose, CA 95131
Telephone (408) 383-1520 (408) 383-1515 -> disconnected
FAX (408) 383-0706 -> disconnected
USNO - List of GPS timing receiver manufacturers -
Stellar GPS - receiver?
Information on NTP Time Servers and Radio Timecode Receivers -
Stanford Telecommunications 5001
Test Transmitter - included is a block diagram showing how
are generated without encryption.
TrueTime Model Mark V GPS receiver, has some similarity.
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Page created 23 July 2001.