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Microchip Technology GPS-2700, User Manual

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Microchip Technology GPS-2700 User Manual Download Page 62

GPS-2700 User’s Guide

DS50003016A-page 62

 2020 Microchip Technology Inc.

3.11.14 CSAC:LIFE?

This query returns the accumulated number of hours that the CSAC has been powered 
on since the last factory reset of the GPS-2700 board. The value is stored in the exter-
nal NV memory and updated every hour when the CSAC is powered on.

3.11.15 CSAC:ST:LAT ONCE

This command stores the momentary steering offset into the CSAC internal NV mem-
ory. This is done automatically by the firmware once every 24 hours, so as not to dam-
age the CSAC NV memory which has a limited number of write cycles. The user may 
force this value to be stored into the CSAC by issuing the CSAC:ST:LAT ONCE com-
mand.

3.11.16 CSAC:TYPE?

GPS-2700 with firmware revision 0.75 and later adds support for querying the model of 
CSAC on the GPS-2700 board.

3.11.17 CSAC:LOCK?

GPS-2700 with firmware revision 0.75 and later adds support for querying the lock sta-
tus of the CSAC. A value of 1 is returned if the CSAC is in atomic lock.

3.11.18 CSAC:POW <ON | OFF>

GPS-2700 with firmware revision 0.74 and later adds support for sending the CSAC 
into Ultra-Low Power (ULP) mode. By default the normal power mode is ON and send-
ing CSAC:POW OFF command will put the CSAC in ULP mode.
The CSAC may loses atomic lock while in ULP mode. Microchip thus recommends 
keeping the CSAC:POW ON setting for normal operation and optimal performance on 
GPS-2700.
This command has the following format:

CSAC:POW <ON | OFF>

The following command returns the current power setting where ON means normal 
power mode:

CSAC:POW?

3.11.19 CSAC?

This command returns the result of the following queries:

CSAC:TYPE?
CSAC:LOCK?
CSAC:RS232?
CSAC:ST?
CSAC:STAT?
CSAC:AL?
CSAC:MODE?
CSAC:CONT?
CSAC:LAS?
CSAC:TCXO?
CSAC:SIG?
CSAC:HEAT?
CSAC:TEMP?
CSAC:SN?

Summary of Contents for GPS-2700

Page 1: ...2020 Microchip Technology Inc DS50003016A GPS 2700 User s Guide...

Page 2: ...work you may have a right to sue for relief under that Act Trademarks The Microchip name and logo the Microchip logo Adaptec AnyRate AVR AVR logo AVR Freaks BesTime BitCloud chipKIT chipKIT logo Cryp...

Page 3: ...ion to the other This material consists of a brief description of GPS 2700 design supported by block diagrams description of environmental issues installation guidelines and unit opera tion WHO SHOULD...

Page 4: ...ters A dialog button Click OK A tab Click the Power tab N Rnnnn A number in verilog format where N is the total number of digits R is the radix and n is a digit 4 b0010 2 hF1 Text in angle brackets A...

Page 5: ...mportant information which may make your task easier or increase your understanding WHERE TO FIND ANSWERS TO PRODUCT AND DOCUMENT QUESTIONS For additional information about the products described in t...

Page 6: ...est software releases and archived software General Technical Support Frequently Asked Questions FAQs technical support requests online discussion groups Microchip consultant program member listing Bu...

Page 7: ...2 Operating Principles 13 1 3 General Safety Precautions 14 1 3 1 Use an Approved Antenna Lightning Protector 14 1 3 2 Grounding 14 1 3 3 Power Connections 14 1 3 4 Environmental Conditions 14 Chapter...

Page 8: ...ZDA int 0 255 37 3 3 17 GPS DYNAM MODE int 0 7 38 3 3 18 GPS DYNAM MODE 8 Automatic Dynamic Mode 39 3 3 19 GPS DYNAM STAT 39 3 3 20 GPS REF ADEL float s ns 32767ns 32767ns 40 3 3 21 GPS REF PUL SAW 40...

Page 9: ...9 3 6 6 SYNC SOUR STAT 49 3 6 7 SYNC TINT 49 3 6 8 SYNC IMME 49 3 6 9 SYNC FEE 49 3 6 10 SYNC LOCK 49 3 6 11 SYNC OUT 1PPS RESET ON OFF 49 3 6 12 SYNC OUT 1PPS RESET 50 3 6 13 SYNC OUT 1PPS WIDTH int...

Page 10: ...00 0 500 0 57 3 10 10 SERV 1PPS int ns 5000000 5000000 57 3 10 11 SERV TRAC PORT RS232 USB 57 3 10 12 SERV TRAC int 0 255 57 3 10 13 SERV EFCS FAST float 0 0 500 0 58 3 10 14 SERV EFCD FAST int 2 4000...

Page 11: ...PSCon Utility 5 1 Description 67 5 2 Installation 67 5 3 Using GPSCon 67 5 3 1 Setting the Options 67 5 3 1 1 Communication Parameters 68 5 3 1 2 Auxillary Parameters 68 5 3 1 3 Traces Parameters 68 5...

Page 12: ...GPS 2700 User s Guide DS50003016A page 12 2020 Microchip Technology Inc NOTES...

Page 13: ...hat runs a Real Time OS a low noise 10 MHz distribu tion amplifier with four highly Isolated 10 MHz Sine Wave outputs one 5 MHz CMOS output one 1PPS UTC synchronized CMOS output RS 232 and USB control...

Page 14: ...is improved typically by 10 dB and more above 8 Hz offset from the carrier and spur performance is improved significantly Software commands allow the cleanup phase noise filter to be switched in and o...

Page 15: ...under Windows XP 7 8 or later as Win dows has the required USB driver already built in Once installed the unit should simply show up as a new Serial Comm Port and the operator may use Hyperterminal Te...

Page 16: ...on Once the green LED is on the unit will output 10 MHz and 5 MHz on the outputs with significantly better than 1ppb frequency accuracy Please note that the GNSS receiver establishes the internal ant...

Page 17: ...is okay and the CSAC is locked to GPS 3 3V CMOS output can drive up to 5 mA series termi nated by 33 J1 8 RX_232 RS 232 receive data RS 232 level J1 9 TX_232 RS 232 transmit data RS 232 level J1 10 GP...

Page 18: ...single GNSS system Several of the systems operate at different carrier frequencies so using multiple GNSS systems can increase immunity against jamming which often occurs at only one carrier frequency...

Page 19: ...ions using the automatic self survey Auto Survey with Position Hold feature or it can be used in mobile plat forms Using Position Hold mode improves timing and frequency accuracy especially in GPS cha...

Page 20: ...nection TABLE 2 4 LCD CONNECTOR J3 PINOUT Pin Name 1 CONTRAST 2 5V 3 GND 4 LCD_RS 5 For factory use only 6 LCD_RDWR 7 For factory use only 8 LCD_ENABLE 9 For factory use only 10 LCD_DATA4 11 For facto...

Page 21: ...e 2 1 or by grounding J1 pin 5 Momentarily activating the key cycles through the LCD display pages described in Section 2 4 5 2 LCD Display Pages The LCD page can also be selected with the SYST LCD PA...

Page 22: ...ure 2 7 This page shows the internal ALARM indication of the CSAC oscillator itself 0x0 indicates normal operation Also shows the CSAC Oscillator steering offset required to maintain UTC lock which is...

Page 23: ...The PLL control loop will try to zero this offset over time as the unit follows UTC at NIST in Colorado via the Satellite transmissions FEE indicates the Frequency Error Estimate which is a unit less...

Page 24: ...eet FIGURE 2 10 Navigation Display Page GPS UTC Time Figure 2 11 This page displays the following UTC GPS Time information UTC time hh mm ss GPS time hh mm ss and leapsecond offset seconds FIGURE 2 11...

Page 25: ...al Time Constant Fast Time Constant Loop Behavior Benign Aggressive SERV EFCS 0 6 2 0 SERV PHASECO 1 2 10 0 SERV EFCD 10 5 The commands to control the loop time constants are part of the SERV command...

Page 26: ...14 shows the typical Allan Deviation of the GPS 2700 unit when locked to GPS ADEV performance approaches 1E 13 per day when locked to GPS The plot shows that at averaging intervals of 1000 seconds and...

Page 27: ...d is quite good approaching 5E 12 over 100 000 seconds in this typical plot FIGURE 2 15 Allan Deviation of Free Running CSAC As shown in Figure 2 16 the Phase Noise of the GPS 2700 unit with the Phase...

Page 28: ...noise filter disabled light trace and enabled darker trace Noise performance improve ments by the filter of almost 20 dB can be seen at 1 kHz offsets over the CSAC oscil lator by itself FIGURE 2 17 P...

Page 29: ...Quick Start Instructions 2020 Microchip Technology Inc DS50003016A page 29 FIGURE 2 19 Alternate Comparative Phase Noise Plot...

Page 30: ...GPS 2700 User s Guide DS50003016A page 30 2020 Microchip Technology Inc NOTES...

Page 31: ...lease refer to the document SCPI 99 pdf for details regarding individual SCPI com mand definitions A basic familiarity with the SCPI protocol is recommended when reading this chapter As a Quick Start...

Page 32: ...S SURV STAT GPS INIT DATE yyyy mm dd GPS INIT TIME hour min sec GPS SYST SEL GPS SBAS QZSS GAL BD GLO GPS NMEA TALK GP GN GPS NMEA SVN GP GN GPS JAM GPS FW GPS 3 3 1 GPS SAT TRA COUN This query return...

Page 33: ...th correct UTC synchronization to the 1PPS pulse immediately prior to the data being sent Once set the NMEA command settings will be stored in NV memory and generate out put information even after pow...

Page 34: ...er ID mode between GP and GN for GGA Microchip GGA RMC and ZDA commands See Section 3 3 32 for detailed operations and restrictions on talker ID mode This command instructs the GPS 2700 to send the NM...

Page 35: ...rging satellite information for other GNSS systems in GPGSV sentence TABLE 3 1 PRN NUMBERING SCHEME FOR GNSS SYSTEMS GNSS Type SV Range GPGSV PRN Vehicle Numbering Talker ID GPS G1 G32 1 32 GP SBAS S1...

Page 36: ...o generate the velocity vector every N seconds with N in the interval 0 255 GPS XYZSP int 0 255 3 3 13 GPS GNGGA int 0 255 GPS 2700 with firmware revision 0 75 and later and uBlox 8 GNSS receiver adds...

Page 37: ...e common 3 3 15 GPS GNRMC int 0 255 GPS 2700 with firmware revision 0 75 and later and uBlox 8 GNSS receiver adds sup port for switching the talker ID mode between GP and GN for GGA Microchip GGA RMC...

Page 38: ...Airborne 1g Airborne applications with less than 1g acceleration 6 Airborne 2g Airborne applications with less than 2g acceleration 7 Airborne 4g Airborne applications with less than 4g acceleration 8...

Page 39: ...t per minute are required Alternatively a vehicle velocity of greater than 100 knots will also initiate a switch into airborne 1g mode Without an appropriate climb descent the unit will remain in Auto...

Page 40: ...n changing the antenna for example since the GNSS receiver measures the antenna system s C No right after reset and adjusts its internal antenna amplifier gains accordingly It takes approximately 1 mi...

Page 41: ...ternal RTC DATE manually when operating the unit in GPS denied environ ments This command is compatible to the PTIME OUT ON command described in Section 3 5 5 to allow automatic time and date synchron...

Page 42: ...ing command with invalid parameter or GPS 2700 without uBlox 8 receiver will result in a Command Error response and no change to the configuration Several rules are applied when switching between GN a...

Page 43: ...ll have GNSS specific talker ID listed in Table 3 1 for each GNSS system enabled if talker ID mode is GN This command has the following format GPS NMEA SVN GP GN If talker ID mode is GP sending GPS NM...

Page 44: ...nd resolution will be best when the tilt of any axis is around 0 Degrees The worst performance with an accuracy of only 5 Degrees is when any of the axis are at their 90 Degree angles this is due to t...

Page 45: ...n factors of the accelerom eter system GYRO CAL Due to the nature of the accelerometer chip the Z axis will have the largest error and lowest sensitivity of all three axis The X and Y axis will have t...

Page 46: ...ferenced to UTC time The hour minute and second is returned 3 5 3 PTIM TIME STR This query returns the current 24 hour time suitable for display for example 13 24 56 3 5 4 PTIM TINT This query is equi...

Page 47: ...ly apply a leapsecond correctly if the GNSS antenna is connected to the unit during the actual leapsecond event and may thus miss the leapsecond event entirely 3 5 7 PTIM LEAP PEND This command return...

Page 48: ...nse quantifies the previous holdover The second number in the response identifies the holdover state A value of 0 indicates the receiver is not in holdover a value of 1 indi cates the receiver is in h...

Page 49: ...3 6 7 SYNC TINT This query returns the difference or timing shift between the GPS 2700 1PPS and the GNSS 1PPS signals The resolution is 1E 10 seconds 3 6 8 SYNC IMME This command initiates a near ins...

Page 50: ...bles disables the Phase Noise filter 3 6 15 SYNC OUT FILT This query returns the Phase Noise filter setting 3 6 16 SYNC HEA The SYNC HEA query returns a hexadecimal number indicating the system s heal...

Page 51: ...efault setting is 220 ns allowing a drift of up to 220ns Reaching this selected threshold will cause a jam sync phase normal ization to be initiated which will also cause an indication of the SYNC HEA...

Page 52: ...olute 5 Lifetime 871 3 8 MEASURE SUBSYSTEM The MEASURE subsystem regroups the queries related to parameters that are mea sured on board on the GPS 2700 The list of the commands supported for this subs...

Page 53: ...PRO ON OFF This command enables disables the prompt scpi on the SCPI command lines The prompt must be enabled when used with the software GPSCon Utility This command has the following format SYST COM...

Page 54: ...3 9 10 SYST LCD PAGE This query returns the current page of the LCD 3 9 11 SYST COMM USB BAUD 9600 19200 38400 57600 115200 This command sets the speed of the serial USB port 3 9 12 SYST COMM USB BAUD...

Page 55: ...ce dynamically depending on the environmental effects on the CSAC The AUTO setting will quickly react to phase perturbations and will try to set NORM settings long time constant whenever the unit is i...

Page 56: ...the servo loop This command will be effective only when SERV STAT is NORMAL or SERV MODE is OFF The command sets the Low Pass filter effectiveness of the DAC Values from 5 to 50 are typically used Lar...

Page 57: ...e Integral part of the PID loop Loop instability will result if the parameter is set too high Typical values are 1 0 to 30 0 This command has the follow ing format SERV PHASECO float 500 0 500 0 The f...

Page 58: ...n of the servo loop This command will be effective only when SERV STAT is FAST and SERV MODE is not OFF Controls the Proportional part of the PID loop Typical values are 0 7 to 6 0 Larger val ues incr...

Page 59: ...too high Typical values are 1 0 to 30 0 This command has the follow ing format SERV PHASECO FAST float 500 0 500 0 The following command returns the current value for FAST Phase correction setting SE...

Page 60: ...atus value in 0 9 as shown in Table 3 6 TABLE 3 6 CSAC STATUS DEFINITIONS Status Definition 0 Locked 1 Microwave Frequency Steering 2 Microwave Frequency Stabilization 3 Microwave Frequency Acquisitio...

Page 61: ...laser 3 11 8 CSAC TCXO This query returns the TCXO Tuning Voltage 0VDC to 2 5VDC tuning range 10 ppm 3 11 9 CSAC SIG This query returns the indication of signal level 3 11 10 CSAC HEAT This query ret...

Page 62: ...e model of CSAC on the GPS 2700 board 3 11 17 CSAC LOCK GPS 2700 with firmware revision 0 75 and later adds support for querying the lock sta tus of the CSAC A value of 1 is returned if the CSAC is in...

Page 63: ...SCPI Control Quick Start Instructions 2020 Microchip Technology Inc DS50003016A page 63 CSAC FW CSAC LIFE CSAC POW...

Page 64: ...GPS 2700 User s Guide DS50003016A page 64 2020 Microchip Technology Inc...

Page 65: ...gic utility to upgrade the contents of Flash memory on the GPS 2700 It is available for download on the Flash Magic website http www flashmagictool com Follow the directions given on the website for i...

Page 66: ...ware download Connect a DB 9 serial connector to the GPS 2700 as indicated in Section 2 4 Please note that the unit can only be upgraded through the RS 232 port not through the USB serial port 4 4 1 U...

Page 67: ...erase factory calibration data the unit will not operate and will have to be returned to the factory Checking this box on the ISP utility will void the war ranty 7 Under Step 3 Hex File browse for th...

Page 68: ...GPS 2700 User s Guide DS50003016A page 68 2020 Microchip Technology Inc NOTES...

Page 69: ...from the website and execute the MSI installer Follow the on screen instructions to complete the installation of GPSCon 5 3 USING GPSCON The GPSCon utility has a help file that should be consulted in...

Page 70: ...After pressing the wrench icon you can select the Auxiliary tab to configure auxiliary measurements See Figure 5 3 for an example of an auxiliary measurement You will notice that the Aux1 request str...

Page 71: ...the drop down box in the upper left of the main window as shown in Figure 5 5 Care must be taken when sending these commands so be sure that the command that you select is supported by the GPS 2700 On...

Page 72: ...is is harder to describe than to actually do here is a paraphrase of the above To zoom in The mouse is used to set the left extent and the right extent of the portion of the curve that the user wants...

Page 73: ...Graphics tab in the Options dialog Export allows you to create an image file of the graph and or the satellite trails map You can select which you want by specifying a file for the Graph path and or M...

Page 74: ...ke the same setting if any as the screen display 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...

Page 75: ...SAC senses the temperature change and actively compensate for the change In Figure 5 9 which is a zoom of Figure 5 8 we can see the phase offset error of the CSAC to the UTC GNSS reference We can see...

Page 76: ...GPS 2700 User s Guide DS50003016A page 76 2020 Microchip Technology Inc NOTES...

Page 77: ...00 China Xian Tel 86 29 8833 7252 China Xiamen Tel 86 592 2388138 China Zhuhai Tel 86 756 3210040 ASIA PACIFIC India Bangalore Tel 91 80 3090 4444 India New Delhi Tel 91 11 4160 8631 India Pune Tel 91...

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