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Geneq SXBlue II, Technical Reference Manual

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SXBlue II GPS Series Technical Reference Manual 

 35 

Table 2-3 Serial Port Pin-out, RS-232C Interface Level  

Pin 

Signal 

Description 

2 

TXD 

NMEA 0183, binary, and RTCM output 

3 

RXD 

NMEA 0183, binary, and RTCM input 

5 

GND 

Signal Ground 

7* 

PPS* 

Pulse Per Second (Output) 

9* 

EM* 

Event Marker (Input) 

 

Note - For successful communications, the baud rate of the SXBlue II GPS serial ports 
must be set to match that of the devices to which they are connected.  Chapter 4 
describes the baud rate change command. 

 

 

2.10 Environmental Requirements 

The equipment supplied with the SXBlue II GPS system has specific environmental limits that 
you should ensure are met when storing and using the system.  

The SXBlue II GPS receiver is designed to be stored between -40

°

C and +85

°

C.  The operating 

temperature range is -40

°

C and +85

°

C. Note that Li-Ion battery performance degrades below -

20

°

C. The SXBlue II GPS and antenna are designed to operate in an outdoor environment with 

100% relative humidity, condensing. 

Summary of Contents for SXBlue II

Page 1: ...SXBlue II GPS Series Technical Reference Manual Revision Date July 2012 rev 2 3 ...

Page 2: ...art 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a ...

Page 3: ...abuse improper installation neglect lightning or other electrical discharge or fresh salt water immersion of Products Repair modification or service of Geneq Products by any party other than a Geneq approved service center shall render this warranty null and void Geneq does not warrant claims asserted after the end of the warranty period Geneq does not warrant or guarantee the precision or accurac...

Page 4: ...ATION USE QUALITY PERFORMANCE OR ACCURACY OF ANY PRODUCTS Governing Legislation To the greatest extent possible this warranty shall be governed by the laws of the Province of Quebec Canada In the event that any provision hereof is held to be invalid by a court of competent jurisdiction such provision shall be severed from this warranty and the remaining provisions shall remain in full force and ef...

Page 5: ...oleil driver 14 1 3 2 5 Microsoft Windows with Widcomm s My Bluetooth Places driver 15 1 3 3 Installing the USB Drivers for Microsoft Windows 17 1 4 In the Field 19 1 4 1 Using the Carrying Case 19 1 4 2 Definition of the LED Indicators 19 1 4 3 GIS Field Data Collection and Datum Considerations 21 1 4 3 1 Generic Field Data Collection Software Configuration 21 1 4 3 2 General Guidelines for GIS F...

Page 6: ...Available Applications 43 3 3 2 2 Activating an Application or Option 45 3 3 2 3 Interpreting Subscription Date Codes 46 3 4 Differential Correction Operations 47 3 4 1 DGPS RadioBeacon Operation SXBlue II B GPS 47 3 4 1 1 Automatic Mode 47 3 4 1 2 Manual Mode 48 3 4 1 3 Database Mode 48 3 4 1 4 Evaluating Performance 49 3 4 2 Activating an OmniSTAR VBS Service SXBlue II L GPS 50 3 4 3 RTCM Input ...

Page 7: ...PMSK 76 4 5 2 PCSI 1 and PCSI 2 77 4 5 3 PCSI 3 2 78 4 5 4 PCSI 3 3 78 4 5 5 PCSI 0 79 4 5 6 PCSI 8 NITRAM 79 4 5 7 GPCRQ MSK CRMSK 80 4 5 8 GPCRQ MSS CRMSS 80 4 6 OmniSTAR Commands SXBlue II L GPS 81 4 6 1 JLBEAM 81 4 6 2 JLXBEAM 82 4 6 3 JFREQ 83 4 6 4 JOMS 84 4 7 Auto Dif Commands in Autonomous Mode 84 4 7 1 JRAD 1 85 4 7 2 JRAD 1 P 85 4 7 3 JRAD 1 lat lon alt 85 4 7 4 JRAD 2 86 4 7 5 JRAD 3 86...

Page 8: ...00 4 10 12 RD1 Data Message 101 4 11 RAIM Command and Message 102 4 11 1 JRAIM Command 102 4 11 2 PSAT GBS Data Message 103 5 Binary Data 105 5 1 Binary Message Structure 105 5 1 1 Bin 1 106 5 1 2 Bin 2 107 5 1 3 Bin 80 108 5 1 4 Bin 93 108 5 1 5 Bin 94 109 5 1 6 Bin 95 110 5 1 7 Bin 96 110 5 1 8 Bin 97 111 5 1 9 Bin 98 112 5 1 10 Bin 99 113 6 Frequently Asked Questions 115 6 1 General 115 6 2 Sup...

Page 9: ...SXBlue II GPS Series Technical Reference Manual ix Appendix A Specifications 124 Appendix B Interface 125 Appendix C Introduction to GPS and DGPS Services 128 Appendix D Resources 140 Index 143 ...

Page 10: ...5 Figure 2 2 Auto Dif Error Drift 30 Figure 2 3 RS 232 Connector Pin out 34 Figure 3 1 Sample Config File 42 Figure B 1 Serial Interface 125 Figure B 2 RTCM Data Output From Serial Port 126 Figure B 3 RTCM Data Input to Serial Port 127 Figure C 1 WAAS Ground Segment end of 2007 135 Figure C 2 EGNOS Ground Segment end of 2007 136 Figure C 3 Worldwide SBAS Coverage 137 Figure C 4 Worldwide SBAS Iono...

Page 11: ...erential Commands 90 Table 4 10 Output Data Messages 95 Table 4 11 GNS Data Message Defined 96 Table 4 12 GGA Data Message Defined 96 Table 4 13 GLL Data Message Defined 97 Table 4 14 GSA Data Message Defined 97 Table 4 15 GST Data Message Defined 98 Table 4 16 GSV Data Message Defined 98 Table 4 17 RMC Data Message Defined 99 Table 4 18 RRE Data Message Defined 99 Table 4 19 VTG Data Message Defi...

Page 12: ...m post processed and single frequency RTK applications It also features independent Bluetooth USB and serial communications This document is meant to assist a customer in becoming familiar with the SXBlue II GPS functionality and system operation but also with GPS SBAS OmniSTAR Radio Beacon RTK concepts The chapters that follow provide detailed information on the SXBlue II GPS receivers including ...

Page 13: ...iant port and One full duplex serial port can be used to configure the product or to output receive RTCM corrections Integrated Li Ion battery for full day operation Organization This manual contains the following chapters Chapter 1 Getting Started provides information to help you get your system running quickly Chapter 2 Features and Performance introduces you to the SXBlue II GPS and some of its...

Page 14: ... available from 8 30 AM to 5 00 PM Eastern Time Monday to Friday To expedite the support process please have the product model and serial number available when contacting Geneq Customer Service In the event that your equipment requires service we recommend that you contact your dealer directly However if this is not possible you must contact Geneq Customer Service to obtain a Return Merchandise fo...

Page 15: ...ormation regarding the installation configuration and operation of the SXBlue II GPS receiver Note Notes outline important information of a general nature Cautions Cautions inform of possible sources of difficulty or situations that may cause damage to the product Warning Warnings inform of situations that may cause harm to you ...

Page 16: ...t the packing slip Unless your system has been equipped differently than a standard SXBlue II GPS you should find the following parts in your package One SXBlue II GPS Receiver with battery pack One Precision Antenna GPS GPS L Band or GPS Beacon One Antenna cable One RS 232 cable One USB cable One Li Ion Battery Charger One Soft Hat for antenna SXBlue II GPS and SXBlue II L GPS only One Nylon Carr...

Page 17: ...l 2 Figure 1 1 SXBlue II GPS Main Components Charger Jack ON OFF Button GPS LED Indicators Battery Gauge Indicator Battery Gauge Button RS 232 Port USB Port GPS Antenna Connector SXBlue II Receiver Battery Pack Battery Thumb Screws x4 Serial Number ...

Page 18: ...n 1 3 2 for more information on sample Bluetooth setups 1 2 2 Battery Pack The Lithium Ion battery pack attaches to the receiver with four thumb screws Modular contacts are used to supply power to the receiver Even though the Li Ion battery pack has a built in protection circuitry care must be taken not to short the contacts on the battery pack Also membrane vents are used on both the receiver and...

Page 19: ...re has settled between 0 C and 45 C Temperature range over which battery can be discharged is between 20 C and 60 C Use of the battery outside of the specified range reduces performance and life expectancy When battery reaches end of life insulate terminals with adhesive tape or similar material before disposal 1 2 3 Precision Antennae The Precision GPS GPS L Band or GPS Beacon Antenna supplied wi...

Page 20: ... messages setting up a Bluetooth connection with a PDA or Computer installing the USB drivers on a computer configuring the data collection software for proper operation with the SXBlue II GPS Chapters 2 and 3 present advanced features and configurations of the SXBlue II GPS for other types of applications high output rates carrier phase post processing base station and rover configuration for RTK...

Page 21: ...d from 2 400 to 115 200 baud Table 1 3 Default GPS NMEA Message Output Port GPS NMEA Messages Update Rate Bluetooth GGA GSA GSV VTG ZDA 1 Hz Serial GGA GSA GSV VTG ZDA 1 Hz USB GGA GSA GSV VTG ZDA 1 Hz The SXBlue II GPS outputs standard NMEA messages by default Five basic sentences are output GGA GSA GSV VTG and ZDA All ports are fully independent from one another and can be set to input or output...

Page 22: ... II GPS does not require any password often called pairing secure connection authentication passkey passcode etc This feature must be disabled in the options of the driver you are using Note The SXBlue II GPS does not require any password passkey for secure connection This feature must be disabled in the driver configuration of your PDA Computer Starting with serial numbers 1002Axxx for SXBlue II ...

Page 23: ...luetooth Settings In the Devices tab tap Add new device Once the SXBlue II GPS has been found select it then tap Next The driver will ask for a Passcode at this point do not enter any value and simply hit Next In the next window SXBlue II GPS wants to connect select Yes The driver will ask again for a Passcode at this point enter just a blank space using the keypad ...

Page 24: ...lue II GPS will be added to the list of discovered devices The next step is to assign a COM port number Tap the Com Ports tab then select New Outgoing Port Select the SXBlue II GPS in the list and hit Next Unselect the Secure Connection option and select a COM Port number in this example COM 8 Hit Finish ...

Page 25: ...nication driver On non Bluetooth enabled PDA s a Compact Flash CF or Secure Digital SD Bluetooth card can be used The example in this sub section shows a typical configuration for Socket Communication drivers on Windows Mobile 2003 Tap on the Bluetooth icon in the task bar on the lower right portion of the screen In the popup menu Select Advanced Features then My Bluetooth Device Make sure Use Aut...

Page 26: ...vices Select Tools Device Discovery and hit Next in the Device Discovery Wizard By default the Any Bluetooth device option will be selected Hit Next After the search the SXBlue II GPS will be displayed in the list Check the box next to it hit Next then Finish The SXBlue II GPS will appear with an icon in the Bluetooth Devices window ...

Page 27: ...articular SXBlue II GPS Click on the X to close the window 1 3 2 3 Windows Mobile with WidComm driver Most iPaq series PDA s from Hewlett Packard HP use drivers from Widcomm Inc Below is a typical Bluetooth configuration for these devices Tap the Bluetooth icon on the bottom right corner and from the menu select Bluetooth Settings In the settings window scroll right to the Serial Port tab and only...

Page 28: ... that appears select Explore a Bluetooth device then hit Next Tap Next to allow the wizard to search for a Bluetooth device Once found the SXBlue II GPS will appear in the Bluetooth Browser select it In the Security section of the following screen Use a secure encrypted connection should be unchecked Tap next The SXBlue II GPS shortcut will be created and in this example will be available as COM 8...

Page 29: ...ard From the Classic Display s menu select Bluetooth then Search Devices All nearby Bluetooth devices will be shown Double click on the SXBlue II GPS icon BlueSoleil will detect the SXBlue II GPS as a Serial Port Service Right click on the SXBlue II GPS icon and select Connect Bluetooth Serial Port The assigned COM port number will be displayed in the taskbar once communication is established ...

Page 30: ...the SXBlue II GPS Click on the Bluetooth Setup Wizard option in the Bluetooth Tasks Select the first option in the list I know the service I want to use then hit Next In the Bluetooth Service Selection window select the Bluetooth Serial Port service then click Next In the Bluetooth Device Selection window from the pull down menu select Show all devices After the search the SXBlue II GPS should app...

Page 31: ...figure Button and uncheck the Secure Connection option The COM port number that is assigned to the SXBlue II GPS will be shown in this example COM8 Click Ok to close the Bluetooth Properties window Hit Finish to complete the configuration If the Start the connection option is checked Bluetooth connection will automatically be activated with the SXBlue II GPS ...

Page 32: ...will be the same every time the SXBlue II GPS is connected to this port The installation software can be found on the supplied CD ROM or in the Download section of the http www sxbluegps com web site The software will install two subsets of the driver The Serial Converter and the USB Serial Port emulation In the SXBlue II GPS USB Driver Setup the default location for the driver installation will b...

Page 33: ... connected to the USB port and powered on In Windows go to Start Settings and Control Panel Double click on System to open the System Properties window Select the Hardware tab then click on the Device Manager button Scroll down to and expand the Ports COM LPT category The SXBlue II GPS USB Serial Port will be shown with the COM port number assigned to it ...

Page 34: ... and can also be used with a belt clip or a shoulder strap The pictures below show how to properly run the antenna cable in the carrying case Note that a small opening on the side allows recharging the battery pack without having to remove the receiver from the case Figure 1 4 Carrying Case 1 4 2 Definition of the LED Indicators The SXBlue II GPS features diagnostic LEDs that provide a quick indic...

Page 35: ...icator will illuminate continuously when the SXBlue II GPS has achieved a solid SBAS OmniStar or Radio Beacon lock depending on model with better than a 150 bit error rate BER or when it is successfully receiving externally input RTCM corrections For example if the SBAS BER is higher than 150 but the receiver is still locked this LED will blink showing that lock is marginal Blue Bluetooth this LED...

Page 36: ...he years and the current revision differs greatly from the original one When using SBAS the coordinates will be in ITRF 2000 current epoch When using the SXBlue II L GPS with an OmniStar subscription the datum will be in NAD 83 Original in North America and in ITRF 2000 elsewhere in the world When using the SXBlue II B GPS the datum will depend on the reference frame of the local DGPS Radio Beacon...

Page 37: ... a GPS receiver to download a complete Ionospheric Grid from an SBAS satellite A special feature of the SXBlue II GPS is its ability to extrapolate the downloaded grid see chapter 2 o For forestry applications if SBAS visibility is marginal it is preferable to activate the receiver outside of forest canopy condition let the receiver track the SBAS signal for at least 5 minutes then the data collec...

Page 38: ...n information required for positioning and tracking This is a hands free mode of operation Satellite acquisition quality is described as a signal to noise ratio SNR A higher SNR is indicative of better quality signal reception Note The GPS engine is always operating regardless of the DGPS mode of operation 2 1 2 Positioning Accuracy The SXBlue II GPS is a sub meter horizontally 95 accurate product...

Page 39: ...or featured within the SXBlue II GPS will automatically scan and track the SBAS satellite signals At time of print SBAS signals available are WAAS Central and North America EGNOS Europe MSAS Japan and GAGAN India being deployed with a satellite planned for early 2011 This automatic tracking allows the user to focus on other aspects of their application rather than ensuring the receiver is tracking...

Page 40: ...ent for operation To improve upon the ionospheric map provided by SBAS the receiver extrapolates information from the broadcast ionospheric coverage map extending its effective coverage This allows the receiver to be used successfully in regions that competitive products may not Please note that the process of estimating ionospheric corrections beyond the WAAS broadcast map would not be as good as...

Page 41: ... line of sight wave Ground wave Sky wave The line of sight wave is not significant beyond visual range of the transmitting tower and does not have a substantial impact upon signal reception 2 3 2 Signal Reception Various sources of noise affect beacon reception and include Engine noise Alternator noise Noise from power lines DC to AC inverting equipment Electric devices such as CRT s electric moto...

Page 42: ... distance to a base station as the data content is not composed of a single base station s information but an entire network s information When the SXBlue II L GPS integrated L Band receiver demodulates the proprietary signal it converts it into a local area format for input to the internal GPS receiver standard RTCM SC 104 message Type 1 The SXBlue II L GPS receiver interpolates corrections from ...

Page 43: ...s to perform well at higher latitudes where the signal power is lower and the satellite appears lower on the horizon The BER number indicates the number of unsuccessfully decoded symbols in a moving window of 2048 symbols Due to the use of forward error correction algorithms one symbol is composed of two bits The BER has a default no lock value of 500 As the receiver begins to successfully acquire...

Page 44: ... SBAS correction received in an RTCM format acting basically like a mobile base station or source of differential correction for another receiver Since all communication ports are fully independent the RTCM can be output on one port ex RS 232 while NMEA position data are sent to a different port ex Bluetooth 2 6 2 The L Band Application The SXBlue II L GPS standard configuration is with both the L...

Page 45: ...oftware if not pre installed Positioning with Auto Dif is relatively jump free provided that the SXBlue II GPS maintains lock on at least four satellites at one time The accuracy of positioning will have a slow drift that limits the use of Auto Dif for approximately 35 to 45 minutes however it depends on how tolerable your application is to drift as Auto Dif can be used for longer periods You shou...

Page 46: ...over for a 20cm floating solution Local RTK Rover for 1 3cm fixed single frequency RTK solution with OTF On The Fly capability Local Base Base Station Application to support both Local Dif and Local RTK For the RTK application the baseline length distance between base station and rover should be kept short less than 10km The positioning performance of the receiver in Local Dif and Local RTK modes ...

Page 47: ... distance root mean square 95 to 98 R95 95 radius 95 It is possible to convert from one statistic to another using the following table Using the value where the From row meets the To column multiply the accuracy by this conversion value Table 2 2 Horizontal Accuracy Statistic Conversions To CEP rms R95 2drms CEP 1 1 2 2 1 2 4 rms 0 83 1 1 7 2 0 R95 0 48 0 59 1 1 2 From 2drms 0 42 0 5 0 83 1 For ex...

Page 48: ... GPS WGS G1150 datum which follows ITRF 2000 The GPS antenna included should be mounted pursuant to the following requirements The SXBlue II GPS receiver computes a position based upon measurements from each satellite to the location of the GPS antenna s phase center Mount the GPS antenna in the location for which you desire a position When choosing a location to mount the antenna please ensure th...

Page 49: ... 2 0 of the Bluetooth standard and has been certified As mentioned in the previous chapter the SXBlue II GPS does not support pairing or bonding or authentication using passwords or pass codes passkeys etc The USB port on the back panel is of Type B and requires a driver to be installed on the computer in order to emulate a serial port See section 1 3 3 for driver installation There is one Serial ...

Page 50: ...tch that of the devices to which they are connected Chapter 4 describes the baud rate change command 2 10Environmental Requirements The equipment supplied with the SXBlue II GPS system has specific environmental limits that you should ensure are met when storing and using the system The SXBlue II GPS receiver is designed to be stored between 40 C and 85 C The operating temperature range is 40 C an...

Page 51: ...ode for activation The SXBlue II L GPS features the SBAS WAAS application installed as Application 1 and the LBAND application as Application 2 The default application is the LBAND and the default differential correction is also LBAND When switching to Application 1 the default differential correction source is WAAS The Local Dif RTK Base applications can be added at a later time on either Applica...

Page 52: ... and proprietary NMEA messages These messages are used to configure the receiver and also contain the required information from the SXBlue II GPS You may configure a selection of NMEA 0183 data messages on one port at various update rates each message has a maximum update rate and a different selection of NMEA 0183 messages with different rates on the other port Chapter 4 presents information rela...

Page 53: ...e 6 message contains null information and is broadcast so that a beacon receiver demodulating the data from the broadcast does not lose lock when the beacon station has no new data to transmit Note RTCM is a local area data standard This means that when positioning with external correction input to the SXBlue II GPS from an external source or outputting corrections from the SXBlue II GPS to anothe...

Page 54: ...t on each of the ports and the update rate of each message Setting the maximum differential age cut off Setting the satellite elevation angle cut off mask 3 3 1 Using HyperTerminal HyperTerminal is a free terminal emulation utility within the Microsoft Windows operating system It can be launched from Start Program Accessories Communications HyperTerminal 3 3 1 1 HyperTerminal Setup When you launch...

Page 55: ...K and the communication with the SXBlue II GPS should start immediately The flow of data should look like the following screenshot If you do not see any data streaming out the receiver s port it might be caused by either one of the following two factors All data messages are turned off To verify type a command like JI or JT and the receiver should send a reply at this point you might not see the c...

Page 56: ...lick on OK to close the windows and reconnect to the receiver 3 3 1 2 Sending Individual Commands The NMEA interface for the Serial Port and the Bluetooth Port uses This and Other terminology When interfacing to a port for turning data messages on or off on that same port the port is referred to as This port If you wish to turn a data message on or off on the opposite port to which you are communi...

Page 57: ...ill record the current configuration to non volatile memory The SXBlue II GPS will let you know when the save process has been completed which can take approximately five seconds see following sub section Note When turning messages ON at a specific baud rate make sure the number of messages sent do not saturate or overflow the communication port The Bluetooth port s factory default is 9600 baud an...

Page 58: ...an Application is installed in the SXBlue II GPS see sections 2 6 and 3 1 it needs to be activated with a subscription code 3 3 2 1 Available Applications At time of print of this manual there are currently five 5 Applications available for the SXBlue II GPS and two update rate options that can simply be activated 1 Default SBAS application called WAAS native application factory installed on Appli...

Page 59: ...er receiver operating as base station This Application uses proprietary RTCM and is only compatible with another SXBlue family receiver as base station 5 Local RTK Rover 5cm is a local differential Application in a Base Station Rover application This option offers a fixed RTK solution with OTF On The Fly capability for sub 5 centimeter accuracy and requires the Local Base application on another re...

Page 60: ...plications are loaded onto the receiver and the order in which they appear One example of a line in the response list is JAPP WAAS AUTODIFF In that example WAAS SBAS EGNOS MSAS GAGAN etc is the number one application or application number 1 and AUTODIFF which is the Auto Dif is the other application or application number 2 Use the following command to switch the applications JAPP O O stands for Ot...

Page 61: ... date code of the receiver This section provides information on interpreting the JI and JK subscription date codes An example of the JI and JK subscription date codes is listed below The date code is in bold and underlined text JI 12838 1 7 26022003 01 01 1900 01 01 3000 6 8Hx 38 JK 01 01 3000 0 1 2 or no number The field to the right of the date code in the JK response 0 in this example correspon...

Page 62: ...e the SXBlue II B GPS initiates a Global Search GS examining each available DGPS beacon frequency and recording Signal Strength SS measurements in units of decibel micro volts to the Global Search Table The receiver uses these measured values to compute an average SS noise floor and to sort the frequencies in descending order of SS This initial phase of the GS takes approximately 3 to 4 seconds to...

Page 63: ...fy the frequency only allowing the SXBlue II B GPS to identify the correct MSK bit rate automatically Partial Manual Tune mode Setting manual operation is discussed in Section 4 using the GPMSK NMEA 0183 command Acquisition of a beacon in manual tune mode is dependent upon the data rate of the station In Full Manual Tune mode with an MSK rate of 200 bps signal acquisition should occur within 5 sec...

Page 64: ...e station database and automatically retune to the closest station 2 Signal quality in the area is poor IEC61108 4 requires the receiver to switch away from a station when WER rises above 10 For installations that don t need to comply with IEC61108 4 this threshold can be increased as usable corrections can be obtained for word error rates up to 50 3 4 1 4 Evaluating Performance The SXBlue II B GP...

Page 65: ...given The model SXBlue II L GPS from Geneq inc The Serial Number This number consists of the last 6 digits of the serial number written on the side of the receiver for example 0812L001 810133 These last 6 digits are the internal GPS engine serial number Alternatively the engine serial number can be retrieved with the JI command JI 810133 1 3 09031998 01 06 1998 12 31 2018 3 5 31 Instructions on ho...

Page 66: ...ous mode of Auto Dif operation 3 4 4 1 Start up When you turn the SXBlue II GPS on with the Auto Dif application running it will require a minimum of a few minutes to gather enough satellite tracking information to model the errors for the future up to 10 minutes may be required depending on your environment You do not have to keep the SXBlue II GPS stationary for this process but you should ensur...

Page 67: ... GPS that provide the most precise accuracy A local base station is required for both differential options Most commonly the base station is comprised of a GPS receiver GPS antenna radio transmitter and power source for the radio The base station is typically set up near the working area tracks GPS signals and broadcasts differential corrections to a radio and rover GPS receiver The rover GPS syst...

Page 68: ...to use the proper application LOCDIF for Local Dif or LOCRTK for Local RTK With LOCDIF or LOCRTK as the active application the SXBlue II GPS will be ready to receive proprietary RTCM correction for correct Local Differential operation in OTF On The Fly initialization mode The baud rate of Port B should be set to 9600 and the JDIFF RTK command should be issued See Chapter 4 for a complete list of c...

Page 69: ...d carriage return line feed message terminator An example NMEA sentence follows XXYYY zzz zzz zzz xx CR LF The components of this generic NMEA message example are displayed in Table 4 1 Table 4 1 NMEA Message Elements Element Description Message header character XX NMEA Talker field GP indicates a GPS talker YYY Type of GPS NMEA Message zzz Variable Length Message Fields xx Checksum CR Carriage Re...

Page 70: ...ally needed JQUERY GUIDE This command is used to poll the SXBlue II GPS for its opinion on whether or not it is providing suitable accuracy after the both SBAS and GPS have been acquired up to 5 min JRESET This command is used to reset the configuration of the SXBlue II GPS JSAVE This command is used to save the configuration of the SXBlue II GPS JSHOW This command is used to query the SXBlue II G...

Page 71: ... usually the same as normal but automatically goes to HIGH above 30 m sec 108 Km hr or 67 1 mi hr On HIGH setting larger sudden drops in SNR are tolerated before observation data is discarded from the Navigation solution This may be beneficial when an aircraft is rapidly banking e g crop duster and hence the GPS signal rapidly transitions its entry into the antenna from area of high antenna gain p...

Page 72: ...altitude aiding uses a fixed altitude instead of using one satellite s observations to calculate the altitude The advantage of this feature when operating in an application where a fixed altitude is acceptable is that the extra satellite s observations can be used to betterment of the latitude longitude and time offset calculations resulting in improved accuracy and integrity Marine markets for ex...

Page 73: ...ing format JLIMIT limit CR LF Where Limit is the new limit in meters The receiver will respond with the following message If you wish to verify the current JLIMIT threshold the response to the JSHOW command provides this information 4 2 6 JAPP This command allows you to request the SXBlue II GPS for the currently installed applications and to choose which application to use The SXBlue II GPS by de...

Page 74: ...ng Auto Dif is currently being used Note Other derivatives of the JAPP command are the JAPP 1 CR LF and JAPP 2 CR LF commands that can be used to set the SXBlue II GPS to use the first and second application It s best to follow up the sending of these commands with a JAPP query to see which application is 1 or 2 These two commands are best used when upgrading the firmware inside the SXBlue II GPS ...

Page 75: ...Blue II GPS will reply with the following response 4 2 8 JCONN This command is used to create a virtual circuit between the A and B port if needed This allows you to communicate through the SXBlue II GPS to the device on the opposite port The virtual circuit command has the following form JCONN p CR LF Where the connection type p may be one of the following p Description AB Specify AB in order to ...

Page 76: ...structs the SXBlue II L GPS to use OmniSTAR differential correction while in the LBAND application 4 2 10 JK This command is used by the SXBlue II GPS to enable subscribe to the various applications and options such as Auto Dif Local Dif Local RTK Local Base 10Hz and 20Hz output rates This command will have the following format JK x CR LF Where x is the subscription key provided by Geneq and is 10...

Page 77: ...ave to be more accurate than half a degree lon Longitude component must be entered in decimal degrees This component does not have to be more accurate than approximately a half degree Note This command is not normally required for operation of the SXBlue II GPS 4 2 12 JQUERY GUIDE This command is used to poll the SXBlue II GPS for its opinion on whether or not it is providing suitable accuracy aft...

Page 78: ...ET CR LF JRESET ALL CR LF does everything JRESET does plus it clears almanacs JRESET BOOT CR LF does everything JRESET ALL does plus the following Clears use of the Real Time clock at startup Clears use of backed up ephemeris and almanacs Re boots the receiver when done When the ALL field is present without the square brackets the almanac is also defaulted Issuing this command with this optional d...

Page 79: ...t port is set to a baud rate of 9600 when queried from Bluetooth A or Serial B 2 This line indicates that the other port is set to a baud rate of 9600 3 This line indicates that the USB port C is set to a baud rate of 9600 4 This line indicates that GPGGA is output at a rate of 1 Hz from the other port 5 This line indicates that GPVTG is output at a rate of 1 Hz from the other port 6 This line ind...

Page 80: ...rees A AIR mode indication 60 Maximum acceptable age of correction data in seconds W Current differential mode W indicates WAAS mode When GP is specified for subset the following is an example response provided JSHOW GP GGA 1 0 This response will provide the JSHOW GP message header followed by each message currently being output through the current port and also the update rate for that message 4 ...

Page 81: ...95 1 or 0 Binary message containing ephemeris information 96 10 2 1 or 0 Binary message containing code and carrier phase information 97 10 2 1 0 or 2 Binary message containing process statistics 98 1 or 0 Binary message containing satellite and almanac information 99 10 2 1 0 or 2 Binary message containing GPS diagnostic information When the PORTy data field is specified without the square bracke...

Page 82: ...tput of the GPS engine JAGE This command is used to configure the maximum age of DGPS corrections JOFF This command is used to turn off all data output by the GPS engine JMASK This command allows you to modify the cut off angle for tracking of GPS satellites JNP This command allows to set the number of decimal digits in the GGA and GLL output messages J4STRING This command allows you to configure ...

Page 83: ... 1 or 0 Range residual message GPVTG 10 2 1 0 or 2 Course Over Ground and Ground Speed GPZDA 10 2 1 0 or 2 Time and Date When the PORTy data field is specified without the square brackets and where y is A B or C this command will enact a change in the GPmsg message on the Bluetooth Serial or USB port The SXBlue II GPS will reply with the following response 4 3 2 JAGE This command allows you to cho...

Page 84: ...nse 4 3 4 JMASK This command allows you to change the elevation cut off mask angle for the receiver Any satellites below this mask angle will be ignored even if available The factory default angle is 10 degrees board level default is 5 degrees as satellites available below this angle will have significant tropospheric refraction errors This message has the following format JMASK e CR LF Where the ...

Page 85: ...ud 9600 for serial number prior to 0808A100 The SXBlue II GPS will reply with the following response 4 3 7 JSMOOTH The JSMOOTH command enables the user to change the carrier smoothing interval This command was designed to offer the user flexibility for tuning in different environments You may find a slight improvement in positioning performance using either the short or long smoothing interval dep...

Page 86: ...eness of the speed measurement provided in the GPVTG message The default value of this parameter is 0 0 seconds of smoothing Increasing the time constant will increase the level of speed measurement smoothing The following command is used to adjust the speed time constant JTAU SPEED tc CR LF Where tc is the new time constant that falls within the range of 0 0 to 200 0 seconds The setting of this v...

Page 87: ... set this value If you are unsure of the best value for this setting it s best to be conservative and leave it at the default setting tc in seconds 10 maximum rate of change of course in s You may query the receiver for the current course over ground time constant by issuing the same command without an argument JTAU COG CR LF Note If you are unsure of the best value for the SPEED and COG settings ...

Page 88: ...llowing message JWAASPRN prn1 prn2 Where prn1 indicates the first PRN number and prn2 indicates the second PRN number The PRN numbers for WAAS are 133 and 138 PRN 135 has been lost EGNOS is currently using PRN 120 and 126 but also has PRN 124 for industry testing MSAS currently uses PRN numbers 129 and 137 To change from the current PRN numbers the following message should be used JWAASPRN sv1 sv2...

Page 89: ...te referenced to the horizon Az az Azimuth from the SXBlue II GPS antenna to the SBAS satellite referenced to the horizon To monitor this information for dual SBAS satellites add the ALL variable to the JGEO message as follows JGEO ALL CR LF This will result in an output message similar to the following JGEO Sent 1575 4200 Used 1575 4200 PRN 135 Lon 133 El 9 7 Az 114 0 JGEO Sent 1575 4200 Used 157...

Page 90: ... r PORTy CR LF The message status variable r may be one of the following values r Description 0 OFF 1 ON When the PORTy data field is specified without the square brackets and where y is A B or C this command will turn RTCM data on or off on the Bluetooth Serial or USB port The SXBlue II GPS will reply with the following response 4 5 DGPS Beacon Commands SXBlue II B GPS This section details the NM...

Page 91: ...F mmm M n CR LF If using Database D or Automatic A tuning mode the command has the following form GPMSK D D CR LF or GPMSK A A CR LF Data Field Description fff f This field is the beacon frequency in kHz 283 5 to 325 and may be left null if the following field is set to automatic A or Database D F This field selects the frequency selection mode either Manual M or Automatic A or Database D mmm This...

Page 92: ...N fff f F mmm M SS SNR MTP WER ID H T G Data Field Description CSx CS0 for channel 0 from PCSI 1 or CS1 for channel 1 from PCSI 2 Pxxx y yyy Resident Beacon engine firmware version SN Internal Beacon engine serial number fff f Beacon frequency being searched or tracked in kHz 283 5 to 325 F Frequency mode of the receiver either Manual M or Automatic A or Database D mmm MSK bit rate being searched ...

Page 93: ...se Time Not implemented Date Not implemented Currently displays as 0 Distance Calculated in nautical miles Health 1 not updated 8 undefined 0 7 valid range WER 1 not updated 0 100 valid range Example PCSI ACK 3 2 PCSI 3 2 929 St Jean QC 2960 0 14 0 0 1 1 PCSI 3 2 919 Cardinal ON 3060 0 94 0 0 1 1 PCSI 3 2 927 Lauzon QC 3090 0 123 0 0 1 1 PCSI 3 2 844 Hudson Falls NY 3240 0 136 0 0 1 1 PCSI 3 2 800...

Page 94: ...5 16441 2242 1 1 PCSI 3 3 0820 0821 0491 Mohrdorf 3080 19777 2254 1 0 PCSI 3 3 0732 1024 0466 Kullen 2930 20493 2266 1 0 PCSI 3 3 0733 1024 0467 Hjortensudde 3020 21343 2305 1 0 PCSI 3 3 1024 1024 1024 St Vito lo Capo 3065 13899 2317 1 1 4 5 5 PCSI 0 This command queries the SXBlue II B GPS for a list of available proprietary PCSI beacon commands must be entered in Capital letters PCSI 0 CR LF The...

Page 95: ...beacon frequency in kHz 283 5 to 325 F This field shows the frequency selection mode either Manual M or Automatic A or Database D mmm This field is the MSK bit rate M This field shows the MSK rate selection mode either Manual M or Automatic A or Database D n Period of output of performance status message 0 to 100 seconds CRMSS 4 5 8 GPCRQ MSS CRMSS This standard NMEA query prompts the SXBlue II B ...

Page 96: ...ns provide detailed information relating to the use of each command Note Please ensure that you save any changes that you wish to survive beyond the current power up by using the JSAVE command and wait for the Save Completed response 4 6 1 JLBEAM This command displays the current spot beams used by the OmniSTAR built in engine This command has the following layout JLBEAM CR LF The receiver will ou...

Page 97: ... 74 52 1200 9999 JLBEAM 1557 8550 122 45 1200 9999 JLBEAM 1535 1375 85 2 1200 98 JLBEAM 1535 1375 60 25 1200 98 JLBEAM 1535 1375 142 15 1200 98 JLBEAM 1535 1375 109 2 1200 109 JLBEAM 1535 1375 140 38 1200 109 JLBEAM 1537 4400 23 2 1200 25 JLBEAM 1537 4400 14 59 1200 25 JLBEAM 1537 4400 11 28 1200 25 4 6 2 JLXBEAM This command displays the current spot beams used by the OmniSTAR built in engine Thi...

Page 98: ...e OmniSTAR satellite frequency This command has the following structure JFREQ freq symb CR LF Where freq is the frequency in KHz and symb is the symbol rate 1200 or 2400 baud The receiver will reply with the following response Entering a frequency of zero with no associated symbol rate will place the OmniSTAR engine into automatic mode Entering a valid frequency and symbol rate will manually tune ...

Page 99: ...nomous Mode This current section provides information related to the NMEA messages accepted by the SXBlue II GPS optional Auto Dif application The following table provides a brief description of the commands supported by the Auto Dif application for its control and operation in Autonomous mode The following section 4 8 provides information on using Auto Dif in Base Station mode Table 4 7 Auto Dif ...

Page 100: ...ative mode as no absolute point information is specified The JRAD 2 command will need to be issued after this command This command has the following format JRAD 1 P CR LF The SXBlue II GPS will reply with the following response JRAD 1P OK 4 7 3 JRAD 1 lat lon alt This command is a derivative of the JRAD 1 P command and is used when absolute positioning is desired The JRAD 2 command will need to be...

Page 101: ...ith the Auto Dif application active The second purpose is to update the Auto Dif solution calibration using the current position as opposed to the reference position used by the JRAD 2 command This command has the following format JRAD 3 CR LF The receiver will respond with the following command if it has tracked enough satellites for a long enough period before you sent the command This period of...

Page 102: ...re that you save any changes that you wish to survive beyond the current power up by using the JSAVE command and wait for the Save Complete response 4 8 1 JRAD 1 This command is used to display the current reference position This command has the following format JRAD 1 CR LF The SXBlue II GPS will reply with a response similar to the following JRAD 1 51 00233513 114 08232345 1050 212 Upon startup ...

Page 103: ... 5101 04028 N 11402 38289 W 2 07 1 4 1071 0 M 17 8 M 6 0 0122 48 ellipsoidal height 1071 0 17 8 1053 2 meters The SXBlue II GPS will reply with the following response JRAD lat lon alt Note Both latitude and longitude must be entered as decimal degrees The receiver will not accept the command if there are no decimal places 4 8 4 JRAD 2 This command is used to force the receiver to use the new refer...

Page 104: ...n feature and uses the previously entered point either with JRAD 1 P or JRAD 1 lat long alt as the reference with which to compute Base Station corrections When using this command the position output by the receiver will not vary as opposed to the JRAD 2 and is the preferred method This command has the following format JRAD 9 1 1 CR LF The receiver will reply with the following response JRAD 9 OK ...

Page 105: ...tivate RTK output on a communication port JRTK 12 Rover Enable Disable the receiver to go into fixed integer mode JRTK 18 Rover Display distance to base station Note The SXBlue II GPS stores two different reference positions in distinct memory locations The first is called Manual Reference and the other is called Auto Reference that the receiver obtains automatically by averaging JRTK 1 returns th...

Page 106: ...to display the manual reference position currently stored in the receiver s internal memory This command has the following format s JRTK 1 CR LF for the manual reference position JRTK 1 Other CR LF for the auto reference auto averaged position The SXBlue II GPS will reply with a response similar to the following JRTK 1 51 00233513 114 08232345 1050 212 4 9 2 JRTK 1 P This command records the curre...

Page 107: ...l separation both available from the GGA sentence See example below Example of ellipsoidal height calculation GPGGA 173309 00 5101 04028 N 11402 38289 W 2 07 1 4 1071 0 M 17 8 M 6 0 0122 48 Ellipsoidal height 1071 0 17 8 1053 2 meters The SXBlue II GPS will use this reference position immediately and reply with the following response JRTK lat lon alt Note Both latitude and longitude must be entere...

Page 108: ... JRTK 9 This command saves the averaged base station location that was determined during the base station s averaging process This is saved to non volatile memory and overwrites the location used by the JRTK 1 command Note that the base station may determine that averaging is not needed and instead use a previous location If this is the case then JRTK 9 will actually re save the previous location ...

Page 109: ...he PORTy data field is specified without the square brackets and where y is A B or C this command will turn RTCM data on or off on the Bluetooth Serial or USB port The SXBlue II GPS will reply with the following response 4 9 10 JRTK 12 This command is used to enable or disable the rover to go into a fixed integer solution mode i e RTK mode This command has the following format JRTK 12 Allow CR LF ...

Page 110: ...GPGNS hhmmss ss llll ll s yyyy yy t n qq pp p saaaaa aa M xxxx xx M sss aaaa cc CR LF Message Max Rate Description GPGNS 20 Hz Fix data for single or combined satellite navigation systems GPGGA 20 Hz Global Positioning System Fix Data GPGLL 20 Hz Geographic Position Latitude Longitude GPGSA 1 Hz GNSS Global Navigation Satellite System DOP and Active Satellites GPGST 1 Hz GNSS Pseudorange Error Sta...

Page 111: ...message is broken down into its components This message takes the following form GPGGA hhmmss ss ddmm mmmm s dddmm mmmm s n qq pp p saaaaa aa M xxxx xx M sss aaaa cc CR LF Table 4 12 GGA Data Message Defined Field Description hhmmss ss UTC time in hours minutes seconds of the GPS position ddmm mmmmm Latitude in degrees minutes and decimal minutes s s N or s S for North or South latitude dddmm mmmm...

Page 112: ...essage The GSA message contains GPS DOP and active satellite information Only satellites used in the position computation are present in this message Null fields are present when data is unavailable due to the number of satellites tracked The table below breaks down the GSA message into its components This message has the following format GPGSA a b cc dd ee ff gg hh ii jj kk mm nn oo p p q q r r c...

Page 113: ...i minor axis of error ellipse meters d d Orientation of semi major axis of error ellipse degrees e e Standard deviation of latitude error meters f f Standard deviation of longitude error meters g g Standard deviation of altitude error meters cc Checksum CR LF Carriage return and line feed 4 10 6 GSV Data Message The GSV message contains GPS satellite information Null fields occur where data is not...

Page 114: ...utes w S E or s W for East or West longitude z z Ground speed in knots y y Track made good referenced to true north ddmmyy UTC date of position fix in day month year d d Magnetic Variation in degrees v Variation sense v E East v W West cc Checksum CR LF Carriage return and line feed 4 10 8 RRE Data Message The RRE message contains the satellite range residuals and estimated position error The tabl...

Page 115: ...ound units u K kilometer h cc Checksum CR LF Carriage return and line feed 4 10 10 ZDA Data Message The ZDA message contains Universal Time information The table below breaks down the ZDA data message into its components This message has the following format GPZDA hhmmss ss dd mm yyyy xx yy cc CR LF Table 4 20 ZDA Data Message Defined Field Description hhmmss ss UTC time in hours minutes seconds o...

Page 116: ...of GPS week may be a couple of seconds old WeekNum The GPS week number FreqMHz The L band frequency in MHz 1475 4200 is used for SBAS DSPLocked 1 if DSPStat 1B or 1F BER BER2 Bit error rate bit error rates are given for both SBAS satellites being tracked AGC L band Signal strength DDS 0 0 for SBAS Doppler 0 for SBAS DSPStat A status bit mask for the DSP tracking of SBAS ARMStat A status bit mask f...

Page 117: ...satellites with differential 1 The number of satellites with no differential 4 11RAIM Command and Message RAIM stands for Receiver Autonomous Integrity Monitoring RAIM is a GPS integrity monitoring scheme that uses redundant ranging signals to detect a satellite malfunction that results in a large range error The SXBlue II GPS uses RAIM to alert users when errors have exceeded a user specified tol...

Page 118: ...here are other situations where the probability of false alarm is high due to geometry Because of the geometry you may get excessive faults even though you are actually within the protection radius Again downgrading to a warning prevents excessive faults when the conditions are highly uncertain The philosophy is to only issue a fault if you are relatively certain to within the probability of a fal...

Page 119: ...SXBlue II GPS Series Technical Reference Manual 104 JASC GPGBS 1 CR LF Or to turn the PSAT GBS message off send the following command JASC GPGBS 0 CR LF ...

Page 120: ...SCII sequence BIN The following table provides the general binary message structure Table 5 1 Binary Message Structure Group Components Type Bytes Value Header Synchronization String BlockID a number which tells the type of binary message DataLength the length of the binary messages 4 byte string Unsigned short Unsigned short 4 2 2 BIN 1 2 80 93 94 95 96 97 98 or 99 52 16 40 56 96 128 300 28 68 or...

Page 121: ... to 65536 GPSTimeOfWeek GPS tow sec associated with this message Double 8 0 0 to 604800 0 Latitude Latitude in degrees North Double 8 90 0 to 90 0 Longitude Longitude in degrees East Double 8 180 0 to 180 0 Height Altitude above the ellipsoid in meters Float 4 VNorth Velocity north in m s Float 4 VEast Velocity East in m s Float 4 VUp Velocity up in m s Float 4 Positive StdDevResid Standard deviat...

Page 122: ...4 Individual bits represent satellites GPSUtcDiff Whole seconds between UTC and GPS time GPS minus UTC Unsigned short 2 Positive HDOPTimes10 Horizontal Dilution of precision scaled by 10 0 1 units Unsigned short 2 Positive VDOPTimes10 Vertical Dilution of precision scaled by 10 0 1 units Unsigned short 2 Positive WAAS PRN Bitmask SBAS PRN and tracked or used status masks Unsigned short 2 See below...

Page 123: ... with most significant bit received first Unsigned long 4 x 8 32 5 1 4 Bin 93 This message has a BlockID of 93 and is 56 bytes excluding the header and epilogue This message contains information relating to the SBAS ephemeris The following table describes the contents of this message in order Table 5 5 Bin 93 Message Group Components Type Bytes Value SV Satellite to which this data belongs Unsigne...

Page 124: ...sion parameters The following table describes the details of this message in order Table 5 6 Bin 94 Message Group Components Type Bytes Value a0 a1 a2 a3 AFCRL alpha parameters Double 8 x 4 32 b0 b1 b2 b3 AFCRL beta parameters Double 8 x 4 32 A0 A1 Coefficients for determining UTC time Double 8 x 2 16 tot Reference time for A0 and A1 second of GPS week Unsigned long 4 wnt Current UTC reference wee...

Page 125: ...ed long 4 x 10 40 SF2words 10 Unparsed SF 2 message Unsigned long 4 x 10 40 SF3words 10 Unparsed SF 3 message Unsigned long 4 x 10 40 5 1 7 Bin 96 This message has a BlockID of 96 and is 300 bytes excluding the header and epilogue This message contains phase and code data The following table describes the constituents of this message in order Table 5 8 Bin 96 Message Group Components Type Bytes Va...

Page 126: ...or processor utilization The following table describes the details of this message in order Table 5 9 Bin 97 Message Group Components Type Bytes Value CPUFactor CPU utilization factor Multiply by 450e 06 to get percentage of spare CPU that is available Unsigned long 4 Positive MissedSubFrame The total number of missed sub frames in the navigation message since power on Unsigned short 2 Positive Ma...

Page 127: ...d from the GPS sub frame 4 Byte 1 0 not logged 2 valid Spare Not used at this time Unsigned short 2 Future use AlmanData Structure Array Group Components Type Bytes Value DoppHz Predicted Doppler in Hz for the satellite in question assuming a stationary satellite Short 2 CountUpdate Number of times the almanac has changed for this satellite since the receiver was turned on Byte 1 Positive Svindex ...

Page 128: ...imeDiff Whole seconds between UTC and GPS time GPS minus UTC Byte 1 Positive GPSWeek GPS week associated with this message Unsigned short 2 0 to 65536 GPSTimeOfWeek GPS tow sec associated with this message Double 8 0 0 to 604800 0 ChannelData 12 structures see below containing tracking data for each of the 12 receiver channels Structure array 12x24 288 See following table ClockErrAtL1 The clock er...

Page 129: ...ees Char 1 90 to 90 Azimuth the azimuth in degrees Byte 1 0 to 180 represents 0 to 360 degrees URA User range error from sub frame 1 of the GPS message Byte 1 See ICD GPS 200 Spare Not used at this time Byte 1 Future use CliForSNR Code lock indicator for SNR SNR 10 0 4096 CliForSNR Nose_floor where Nose_floor 80000 0 Unsigned short 2 Positive DiffCorr 100 times the differential correction for this...

Page 130: ...op dusting In this application the aircraft must refuel and be filled with chemicals quite frequently perhaps every 20 minutes This allows for a new initialization when the aircraft lands Provided that the user feels that it s efficient to do so Auto Dif can be successfully used in geographic regions where the only differential services available are subscription based Auto Dif in this application...

Page 131: ...ially if I have a problem with the operation of the SXBlue II GPS module A Try to isolate the source of the problem Problems are likely to fall within one of the following categories It s important to review each in detail to remove each from being a suspect source of the problem Power communication and configuration GPS reception and performance SBAS reception and performance External corrections...

Page 132: ...hat the baud rate of the SXBlue II GPS matches the other device The other device must also support an 8 data bit 1 stop bit and no parity port configuration 8 N 1 Some devices support different settings that may be user configurable Ensure that the settings match 7 Consult the troubleshooting section of the other devices reference manual to determine if there may be a problem with that equipment Q...

Page 133: ...ure that when using HyperTerminal that it is configured to use the correct PC communication port baud rate and that the local echo feature is on see section 3 3 6 5 GPS Reception and Performance Q How do I know what the SXBlue II GPS is doing A The SXBlue II GPS supports standard NMEA data messages The GPGSV data message contains satellite tracking information Since the GPS automatically tracks GP...

Page 134: ... without needing to use NMEA commands Q Does it matter much if the SXBlue II GPS is frequently losing lock on SBAS due to obstructions and the low satellite elevation angles at my geographic location A No provided that the receiver is receiving a full set of corrections relatively often Using the COAST technology the SXBlue II GPS will be able to perform well for up to 40 minutes with old correcti...

Page 135: ...g an 8 data bit no parity and 1 stop bit serial port configuration Inspect the cable connection to ensure there s no sign of damage Check the pin out information for the cables to ensure that the transmit line of the external correction source is connected to the receive line of the SXBlue II GPS s serial port and that the signal grounds are connected 6 9 Installation Q Does it matter where I moun...

Page 136: ...on the RS 232 and USB ports No GPS lock Check integrity of antenna cable Verify antenna s unobstructed view of the sky Verify the lock status of GPS satellites this can often be done on the receiving device or with the use of HyperTerminal running on a PC No SBAS lock Check antenna connections Verify antenna s unobstructed view of the sky If starting the receiver under dense forest canopy move the...

Page 137: ...n has not converged to the accuracy specified by the JLIMIT command and will become solid yellow after the solution has converged The JLIMIT sets the threshold for the RMS residual error and this error gives a rough indication of expected user accuracy Note however that it is not a direct measure of accuracy Factors such as constellation geometry must also be taken into account The default value f...

Page 138: ...SXBlue II GPS Series Technical Reference Manual 123 Appendices ...

Page 139: ...USB interface 2 0 Type B connector Bluetooth Class Version Class 1 Version 2 0 Data Port available baud rates 4800 to 57600 Output protocol NMEA 0183 proprietary binary Input protocol NMEA 0183 External correction input protocol RTCM SC 104 Power Specifications Item Specification Battery type Lithium Ion Battery capacity 3 900mAh 7 2V Battery autonomy 10 hours depending on model Power consumption ...

Page 140: ...put and mode of operating the SXBlue II GPS To establish communications between the SXBlue II GPS receiver and your data logging or navigation device in this mode of operation you must Connect Pin 2 transmit TX of the supplied SXBlue II GPS Serial cable to the receive pin RX of the data logging or navigation device Connect Pin 3 receive RX of the SXBlue II GPS Serial cable to transmit pin TX of th...

Page 141: ...From Serial Port Note For successful communication the baud rate of the SXBlue II GPS Serial port must be set to match that of the separate GPS receiver Additionally you must interface the SXBlue II GPS to an RS 232C serial port of the separate GPS receiver Refer to chapter 4 for instructions related to setting the SXBlue II GPS baud rate using the JBAUD command External Correction Input In this o...

Page 142: ...und of the external correction source Figure B 3 RTCM Data Input to Serial Port Note For successful communications the baud rate of the SXBlue II GPS differential port must be set to match that of the external correction source The correction source must support an RS 232 interface level and the baud rates between each device must match Refer to chapter 4 for instructions related to setting the SX...

Page 143: ...ates Tracking of only three satellites reduces the position fix to 2D coordinates horizontal with fixed vertical The GPS receiver calculates its position with respect to the phase center of the GPS antenna The latitude longitude and altitude of the antenna are referenced according to the current version of the World Geodetic System 1984 ellipsoid WGS 84 At the time of print the current WGS 84 vers...

Page 144: ...eceiver is being operated Depending on receiver hardware and the methodology used for post process performance can be from many centimeters to millimeter precision A variety of 3 rd party software packages are available to post process GPS raw measurement data The SXBlue II GPS can be configured to output raw measurement data at rates of up to 20 Hz in a proprietary format This data can be convert...

Page 145: ...tion This is the predominant DGPS strategy used for a majority of real time applications Positioning using corrections generated by DGPS radiobeacons will provide a horizontal accuracy of 1 to 5 meters with a 95 confidence More sophisticated short range DGPS systems 10 to 15 km can achieve centimeter level accuracy but are expensive and often limited to precise survey applications due to technical...

Page 146: ...to successfully operate than real time systems Factors Affecting DGPS Accuracy Many factors affect the positioning accuracy that a user may expect from a DGPS system The most significant of these influences include Proximity of the remote user to the reference station atmospheric and orbit errors Age of the received differential corrections Atmospheric conditions at the beacon and remote user loca...

Page 147: ...he ionosphere is that it varies from day to day and even hour to hour due to the sun s 11 year solar cycle and the rotation of the earth respectively During the summer of 2001 the sun s solar cycle reached an 11 year high and going forward we saw a general cooling trend of the ionosphere over the few years that followed thus with reduced ionospheric activity Removing the effect of the ionosphere d...

Page 148: ... a few regions of the sky a lower DOP stronger solution will result GPS Signal Multipath Satellite signals received by the GPS receiver by a reflection from an object can decrease positioning accuracy These multipath signals increase the measured range to a satellite as the signal takes a longer route to the GPS antenna Certain precautions will minimize GPS antenna sensitivity to these reflected s...

Page 149: ...ecurity of Air Navigation in Africa and Madagascar have signed a cooperation agreement with the objective of using satellite navigation to improve air traffic safety over the African continent In Japan the MTSAT Satellite based Augmentation System MSAS has been deployed by the Japan Civil Aviation Bureau JCAB Successful launches of MTSAT 1R and MTSAT 2 were followed by system integration for MSAS ...

Page 150: ...lable for each error source rather than the sum effect of errors on the user equipment s range measurements This more effectively manages the issue of spatial decorrelation than some other techniques resulting in a more consistent system performance regardless of geographic location with respect to reference stations Specifically SBAS calculates separate errors for the following The ionospheric er...

Page 151: ...f the ionosphere will be considerably South of your location since the ionosphere is at an altitude of approximately 60 km There must be sufficient ionospheric map coverage beyond your location in order to have ionospheric correctors for all satellites To enhance the information provided by SBAS the SXBlue II GPS has a unique ability to extrapolate the ionospheric information beyond the broadcast ...

Page 152: ...zon Fortunately the COAST Technology helps alleviate this problem by maintaining system performance when SBAS signal loss occurs for extended periods of time More information on COAST is provided in Section 2 5 When using SBAS correction data the SXBlue II GPS is able to provide you with the azimuth and elevation of the SBAS available satellites via a NMEA command to aid in determining their posit...

Page 153: ... of the SBAS Constellations Table C 1 Worldwide SBAS Constellation April 2011 SBAS Constellation PRN Number Satellite Name Longitude WAAS 133 Inmarsat 4F3 98 0 W WASS 135 Galaxy XV 133 0 W WAAS 138 Anik F1R Telesat 107 3 W EGNOS 120 Inmarsat 3f2 AOR E 15 5 W EGNOS 124 ESA Artemis 21 5 E EGNOS 126 Inmarsat IND W 25 0 E MSAS 129 MTSAT 1R 140 0 E MSAS 137 MTSAT 2 145 0 E GAGAN 128 Insat 4G GSAT 8 55 ...

Page 154: ...tion on the ionospheric map features of SBAS and the SXBlue II GPS SBAS Ionospheric Map Extrapolation To improve upon the ionospheric map provided by SBAS the SXBlue II GPS receiver extrapolates a larger ionospheric map from the broadcast coverage map extending its effective coverage This allows the SXBlue II GPS to be used successfully in regions where competitive products may not For example the...

Page 155: ...ent Document RTCA DO 229A Special Committee No 159 RTCA 1998 1828 L Street NW Suite 805 Washington DC 20036 USA Tel 1 202 833 9339 ARIC Research Corporation Interface Control Document Navstar GPS Space Segment Navigation User Interfaces ICD GPS 200 April 12 2000 2250 E Imperial Highway Suite 450 El Segundo CA 90245 3509 www navcen uscg gov gps geninfo default htm Geneq Web Site This following addr...

Page 156: ...ional Association of Marine Aids to Navigation and Lighthouse Authorities IALA http www iala aism org OmniSTAR Web Site http www omnistar com Finding Satellite Elevations The following web page allows computing elevations of satellites above horizon from any location in the world http www lyngsat com Java in browser should be enabled WAAS PRN 133 http www lyngsat com tracker galaxy19 html same loc...

Page 157: ... providing details regarding solar and ionospheric activity http iono jpl nasa gov index html http www spaceweather com http www n3kl org sun noaa html GPS GIS and Survey Related Magazines GPSWorld Magazine http www gpsworld com GPSWorld Survey Construction News http sc gpsworld com gpssc GIM International http www gim international com POB Magazine http www pobonline com Direction Magazine http w...

Page 158: ...Rate 35 124 125 126 Binary 34 37 104 Bit Error Rate WAAS 24 Bluetooth 34 Bluetooth Communication 7 Bluetooth Connectivity 34 C Carrying Case 19 COAST 114 COAST Feature 27 28 Commands 41 Auto Dif 84 87 General 54 GPS 67 Local Differential 89 RAIM 102 SBAS 72 Communication 33 Connectivity 34 124 125 Customer Service xiv D Date Codes 46 Default Application 5 Default GPS NMEA Message Output 6 Default ...

Page 159: ...3 Multipath 132 N NMEA 0183 33 37 54 95 NMEA 0183 messages 54 O Output Data Messages 95 P Performance 23 118 Post Processing 31 Precision Antenna 4 R Real Time Differential Options 28 RTCM SC 104 37 129 S SBAS 24 114 118 127 132 SBAS Coverage 136 SBAS Performance 24 Selective Availability SA 128 Serial Port 34 SNAS 133 System Overview 1 T Temperature 35 Troubleshooting 115 120 Tune Mode WAAS Autom...

Page 160: ...IFF RTK Rev 1 3 April 2009 EGNOS Inmarsat 4f2 to replace 3f5 on PRN 126 PRN 124 set to broadcast Update Fig C4 and Table C1 of AppC Change link to Lyngsat Tracker for PRN 126 AppD New EGNOS RIMS added change AppC Fig C 2 Add EGNOS user support link Update EGNOS web site AppD http 194 224 177 81 Webportal Egnos Pages Home page Rev 2 0 December 2010 SXBlue II B GPS and SXBlue II L GPS receivers adde...

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