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Jackson Labs FireFly-1A GPSDO User Manual

Gps receiver
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FireFly-1A User
Manual
Document:
80200501
Version:
1.2
Date:
6 July, 2011

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Summary of Contents for Jackson Labs FireFly-1A GPSDO

  • Page 1 FireFly-1A User Manual Document: 80200501 Version: Date: 6 July, 2011...
  • Page 2 FireFly-1A User Manual Copyright © 2010, 2011 Jackson Labs Technologies, Inc.

  • Page 3: Table Of Contents

    3.5.8 SYNChronization:LOCKed? ..... 13 3.5.9 SYNChronization:health? ..... . 13 © 2011 Jackson Labs Technologies, Inc.
  • Page 4 5.3.4 Exporting the graphics ..... . . 35 5.4 Interpreting the Data ......36 © 2011 Jackson Labs Technologies, Inc.

  • Page 5: Certification And Warranty

    6.1.2 Limitation of Warranty ......37 6.1.3 Exclusive Remedies ......38 © 2011 Jackson Labs Technologies, Inc.
  • Page 6 FireFly-1A User Manual © 2011 Jackson Labs Technologies, Inc.

  • Page 7: Introduction

    1.2.1 Grounding To avoid damaging the sensitive electronic components in the FireFly-1A GSPDO always make sure to discharge any built-up electrostatic charge to a good ground source, such as power supply ground. This should be done before handling the circuit board or anything connected to it, i.e. the GPS antenna.
  • Page 8 FireFly-1A User Manual © 2011 Jackson Labs Technologies, Inc.

  • Page 9: Quick-Start Instructions

    Connect a clean +12V power supply to J5. The connector style is a MolexPart Number 22-23-2031 connector. Warning: Do not reverse the polarity of the power connector, this will damage the unit. 2.1.1 Major connections The major connections and features of the FireFly-1A PCB are shown in :Figure 2.1. Figure 2.1 Major connections to FireFly-1A...

  • Page 10: Coaxial Connector Types

    Connect the GPS antenna to the BNC to MMCX cable adapter. Caution: use a Lightning Arrestor on your Antenna setup. Use an amplified GPS antenna that is 3V LNA compatible. The FireFly-1A GPS receiver is a 50 channel high-sensitivity GPS receiver with very fast lock time. It does not require any self-survey or position-hold mode (auto survey), and thus can be used in mobile platforms.

  • Page 11: Remote Serial Control

    Phase compensation: this is the Integral part of the PID loop. This corrects phase offsets between the FireFly-1A 1PPS signal and the UTC 1PPS signal as generated by the GPS receiver. Set higher values for tighter phase-following at the expense of frequency stability. Typical values range from 4 - 30, 25 being the default.
  • Page 12 FireFly-1A User Manual Figure 2.2 FireFly-1A phase compensation plot © 2011 Jackson Labs Technologies, Inc.

  • Page 13: Scpi-Control Quick Start Instructions

    Symmetricom 58503A commands.To get a listing of the available commands, send the HELP? query. This will return a list of all the available commands for the FireFly-1A GPSDO. Additional information regarding the SCPI protocol syntax can be found on the following web site: http://www.scpiconsortium.org...

  • Page 14: Gps:satellite

    3.3.4 NMEA Support The following two commands allow the FireFly-1A GPSDO to be used as an industry standard navigation GPS receiver. The GPGGA and GPRMC NMEA commands comprise all necessary information about the antenna position, height, velocity, direction, satellite info, fix info, time, date and other information that can be used by standard navigation applications via the FireFly-1A RS-232 interface.

  • Page 15: Gps:gpgga

    3.3.6 GPS:GGASTat This command instructs the FireFly-1A to send a modified version of the NMEA standard string $GPGGA every N seconds, with N in the interval [0,255]. The command is disabled during the initial 7 minute OCXO warmup phase.

  • Page 16: Gps:position

    PTIME? 3.4.1 PTIMe:TZONe? Returns the local time zone offset. 3.4.2 PTIMe:DATE? This query returns the current calendar date. The local calendar date is referenced to UTC time. The year, month, and day are returned. © 2011 Jackson Labs Technologies, Inc.

  • Page 17: Ptime:time

    PTIME:DATE? PTIME:TIME? PTIME:TZONE? PTIME:TINTerval? 3.5 SYNChronization Subsystem This subsystem regroups the commands related to the synchronization of the FireFly-1A with the GPS receiver. The list of the commands supported for this subsystem is the following: SYNChronization:SOURce:MODE [GPS|EXTernal|AUTO] SYNChronization:SOURce:STATE? SYNChronization:HOLDover:DURation? SYNChronization:HOLDover:INITiate...

  • Page 18: Synchronization:holdover:duration

    This command terminates a manual holdover that was initiated with the SYNC:HOLD:INIT command, and return the unit to normal GPS locking mode. 3.5.5 SYNChronization:TINTerval? This query returns the difference or timing shift between the FireFly-1A 1 PPS and the GPS 1 PPS signals. The resolution is 1E-10 seconds. 3.5.6 SYNChronization:IMMEdiate This command initiates a near-instantaneous alignment of the GPS 1 PPS and Receiver output 1 PPS.

  • Page 19: Synchronization:locked

    ‘Oring’ these values together results in: 0x40 | 0x10 | 0x4 = 0x54 The unit would thus indicate: HEALTH STATUS: 0x54 A health status of 0x0 indicates a properly locked, and warmed-up unit that is completely healthy. © 2011 Jackson Labs Technologies, Inc.

  • Page 20: 10Synchronization

    It returns a value in volts between 0 and 5 V 3.7 MEASURE Subsystem This subsystem regroups the queries related of some parameters that are measured on-board on the FireFly-1A. The list of the commands supported for this subsystem is the following: MEASure:VOLTage? MEASure:CURRent? MEASure? 3.7.1 MEASure:VOLTage?

  • Page 21: Measure:current

    This query returns the result of the two following queries: MEASure:VOLTage? MEASure:CURRent? 3.8 SYSTEM Subsystem This subsystem regroups the commands related to the general configuration of the FireFly-1A. The list of the commands supported for this subsystem follows: SYSTem:COMMunicate:SERial:ECHO <ON | OFF> SYSTem:COMMunicate:SERial:PROmpt <ON | OFF>...

  • Page 22: System:status

    SERVo:TRACe <int > [0,255] SERVo? 3.9.1 SERVo:COARSeDac This command sets the coarse Dac that controls the EFC. The FireFly-1A control loop automatically adjusts this setting. The user should not have to change this value. This command has the following format: SERVo:COARSeDac <int>...

  • Page 23: Servo:efcdamping

    This parameter is a coefficient that represents the drift of the EFC needed to compensate the natural drift in frequency of the OCXO due to aging. This coefficient is automatically computed and adjusted over time by the Jackson Labs Technologies, Inc. firmware. This command has the following format: SERVo:AGINGcompensation <float> [-10.0, 10.0] 3.9.8 SERVo:PHASECOrrection...

  • Page 24: 10Servo:trace

    Holdover, but still phase locked (stays in this state for about 100s after GPS lock is lost) Locked, and GPS active 3.9.11 SERVo? This command returns the result of the following queries: SERVo:COARSeDac? SERVo:DACGain? SERVo: EFCScale? SERVo:EFCDamping? SERVo:SLOPe? SERVo:TEMPCOmpensation? © 2011 Jackson Labs Technologies, Inc.
  • Page 25 FireFly-1A User Manual SERVo:AGINGcompensation? SERVo:PHASECOrrection? SERVo:1PPSoffset? SERVo:TRACe? © 2011 Jackson Labs Technologies, Inc.
  • Page 26 FireFly-1A User Manual © 2011 Jackson Labs Technologies, Inc.

  • Page 27: Firmware Upgrade Instructions

    Firmware Upgrade Instructions 4.1 Introduction The following is a short tutorial on how to upgrade the FireFly-1A GPSDO firmware. Please follow the instructions in-order to prevent corrupting the FireFly-1A Flash, which may require reflashing at the factory. With some practice, the entire Flash upgrade can be done in less than one minute, even though the following seems like a fairly long list of instructions.

  • Page 28: Putting The Pcb Into In-Circuit Programming (Isp) Mode

    OWER 4.4 Downloading the firmware Download the latest version of FireFly-1A firmware from the Jackson Labs Technologies, Inc. support website and store it in a place that will be remembered. The file is in .hex format. The unit needs to be connected to the computer’s RS-232 serial port prior to firmware download.
  • Page 29 Please note that the “Use Baud Rate” setting needs to be set to 38400 Baud or less, it will not work faster than 38400 Baud. The “DEVICE” should show up as “LPC2138” after pressing “READ DEVICE ID” © 2011 Jackson Labs Technologies, Inc.

  • Page 30: Flash Magic Flash Programming Utility

    RENDER THE PCB USELESS AND CAN ONLY BE RECOVERED AT THE FACTORY! 4.4.2 Flash Magic Flash Programming Utility A) Open the Flash Magic utility. Set the COM port in the Flash Magic application as needed on your PC. Set “Interface” to “None (ISP)”. © 2011 Jackson Labs Technologies, Inc.
  • Page 31 FireFly-1A User Manual Figure 4.4 Flash Magic utility B) Press the “Select Device” button and the window shown in Figure 4.5 will appear: © 2011 Jackson Labs Technologies, Inc.
  • Page 32 FireFly-1A User Manual Figure 4.5 Device selection window C) Expand the ARM7 folder and select the appropriate processor, in this case the LPC2138. © 2011 Jackson Labs Technologies, Inc.

  • Page 33: Verifying Firmware Update

    During power on, the unit sends an ID string out of the serial port at 115200 Baud by default. The firmware version can also be queried by sending the *IDN? command. Verify that the firmware version is the version that was downloaded. © 2011 Jackson Labs Technologies, Inc.
  • Page 34 FireFly-1A User Manual © 2011 Jackson Labs Technologies, Inc.

  • Page 35: Gpscon Utility

    To set up the options for your GPSCon session, press the “Options” button below the display area. The window shown in Figure 5.1 will appear. You can select from the tabs which options you wish to set. © 2011 Jackson Labs Technologies, Inc.

  • Page 36: Communication Parameters

    “Aux 1 request string” has been set to meas:current?<CD> and the “Log Aux1” box is checked. In the area below labeled “Traces to be visible on the graph”, the box “Aux 1” is checked and the label “OCXO curr” has been added. © 2011 Jackson Labs Technologies, Inc.
  • Page 37 FireFly-1A User Manual Figure 5.2 Setting the communications parameters © 2011 Jackson Labs Technologies, Inc.

  • Page 38: Other Options

    Figure 5.4. Care must be taken when sending these commands so be sure that the command that you select is supported by the FireFly-1A GPSDO. Once you’ve selected the command, you can press “Send” to send it to the FireFly-1A.

  • Page 39: Use Of The Mouse In Graph Mode

    And, finally to return to the zoomed out ("fit to window") view, left double-click on the curve." © 2011 Jackson Labs Technologies, Inc.
  • Page 40 Shift + Right click. Double left click to release everything. The time span indication at the lower right of the graph will turn red to signify that mouse override is in effect. Figure 5.5 Graph display © 2011 Jackson Labs Technologies, Inc.

  • Page 41: Exporting The Graphics

    The export may be done automatically on a timed basis. Simply enter a non-zero value in seconds to choose an export time interval. To manually export in accordance with the settings, press the 'Export' button. © 2011 Jackson Labs Technologies, Inc.

  • Page 42: Interpreting The Data

    5.4 Interpreting the Data Figure 5.5 shows the data acquired by the FireFly-1A unit over a period of more than 200 hours The red trace is EFC (crystal frequency control voltage). The crystal is aging (becoming faster in frequency over time). This requires the control voltage to be lowered to maintain 10.0MHz exactly.

  • Page 43: Certification And Warranty

    This Jackson Labs Technologies, Inc. hardware product is warranted against defects in material and workmanship for a period of 1 (one) year from date of delivery. During the warranty period Jackson Labs Technologies, Inc. will, at its discretion, either repair or replace products that prove to be defective.

  • Page 44: Exclusive Remedies

    FireFly-1A User Manual PURPOSE. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Jackson Labs Technologies, Inc. products are not intended for use in medical, life saving, or life sustaining applications.

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