USGlobalsat ET-314 User Manual

ET-314

Version 1.2

GPS Engine Board ET-314

Version 1.2

06/22/2007

Globalsat Technology Corporation Headquarters (Far East Century Park)

16F., No. 186, Jian-Yi Road, Chung-Ho City, Taipei Hsien 235, Taiwan

Tel: 886-2-8226-3799/ Fax: 886-2-8226-3899

E-mail : service@globalsat.com.tw

Website: www.globalsat.com.tw

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ET-314

Version 1.2

1. Product Information



Product Name: ET-314

Product Description:



ET-314 is a compact, high performance, and low power consumption GPS engine board. It uses SiRF

Star III chipset which can track up to 20 satellites at a time and perform fast TTFF in weak signal

environments. ET-314 is suitable for the following applications:

‧ Automotive navigation ‧ Personal positioning ‧ Fleet management ‧ Marine navigation

 Product Features:

 SiRF star III high performance GPS Chipset  Very high sensitivity (Tracking Sensitivity: -159 dBm)  Extremely fast TTFF (Time To First Fix) at low signal level  Two serial ports  4Mb flash  Compact size (25.4mm * 25.4 mm * 3.3mm) suitable for space-sensitive application  One size component, easy to mount on another PCB board  Support NMEA 0183 and SiRF binary protocol

 Product Specifications

Chipset

Frequency L1, 1575.42 MHz

Code C/A Code

Protocol NMEA 0183 v2.2

GPS Receiver

SiRF StarⅢ

Default:GGA,GSA,GSV,RMC

Support:VTG,GLL,ZDA)

SiRF binary and NMEA Command

Available Baud Rate 4,800 to 57,600 bps adjustable

Channels 20

Flash 4Mbit

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Sensitivity Tracking:-159dBm

Cold Start 42 seconds, average

Warm Start 38 seconds, average

Hot Start 1 second, average

Reacquisition 0.1 second, average

Accuracy Position: 10 meters, 2D RMS

5 meters, 2D RMS, WAAS enabled

Velocity: 0.1 m/s

Time: 1us synchronized to GPS time

Version 1.2

Maximum Altitude

Maximum Velocity

Maximum Acceleration

Update Rate 1 Hz

DGPS WAAS, EGNOS, MSAS

Datum WGS-84

I/O Pins 2 serial ports

Type 30-pin stamp holes

Dimensions 25.4 mm * 25.4 mm * 3.3 mm

Power Supply

Backup Voltage

Power Consumption

＜ 18,000 meter

＜ 515 meter/second

＜ 4G

Interface

Physical Characteristic

DC Characteristics

3.3Vdc ± 5%

2.0 ~ 3.6Vdc ± 10%

Acquisition: 42mA Tracking: 25mA

Environmental Range

Humidity Range 5% to 95% non-condensing

Operation Temperature

Storage Temperature

-40℃ to 85℃

-40℃ to 125℃

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ET-314

2. Technical Information

 Block Diagram

Version 1.2

 Module Pin Assignment:

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Pin Signal Name I/O Description

1 VCC I DC Supply V oltage input 2 GND G Ground 3 Boot select I Boot mode 4 RXA I Serial port A 5 TXA O Serial port A 6 TXB O Serial port B 7 RXB I Serial port B 8 GPIO14 I/O General –purpose I/O 9 RF_ON

10 GND G Digital Ground

Version 1.2

11

16 17 RF_IN I GPS Signal input 18 GND_A G Analog Ground 19 V_ANT_IN I Active Antenna Bias voltage 20 VCC_RF O Supply Antenna Bias voltage 21 V_BAT I Backup voltage supply 22 Reset I Reset (Active low) 23 GPIO10 I/O General purpose I/O 24 GPIO1 I/O General purpose I/O 25 GPIO5 I/O General purpose I/O 26 GPIO0 I/O General purpose I/O

27 GPIO13 I/O General purpose I/O 28 GPIO15 I/O General purpose I/O 29 PPS O One pulse per second

GND_A G Analog Ground

(support continuous power mode only)

30 GND G Digital Ground

Definition of Pin assignment

VCC

This is the main DC supply for a 3.3V +- 5% DC input power module board.

GND

GND provides the ground for digital pa

rt.

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Boot select

Set this pin to high for programming flash.

RXA

Version 1.2

This is the main receiver channel and is used to receive software commands to the board from SIRFdemo software or from user written software. PS:

RXB

Pull up

if

not used.

This is the auxiliary receiving channel and is used to input differential corrections to the board to enable DGPS navigation. PS:

TXA

Pull up

if

not used.

This is the main transmitting channel and is used to output navigation and measuremen

TXB

t

data to SiRFdemo or user written software.

For user’s application (not currently used).

RF_ON

This pin indicates state of RF voltage.

RF_IN

This pin receiver signal of GPS analog .due to the RF characteristics of the signal the design has to certain criteria. The line on the PCB from the antenna(or antenna connector) has to be a controlled microstrip line at 50Ω

V_ANT_IN

This pin is reserved an external DC power supply for active antenna. If

using 3.3V active antenna, pin 19 has to be connected to pin 20.

If the bi as voltage of active isn’t 3.3V

,you can input bias voltage of you need to this pin.

VCC_RF

This pin provides DC voltage 3.3 for active antenna. Reset

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ET-314

Version 1.2

This pin provides an active-low reset input to the board. searching for satellites.

PPS

This pin provides one pulse-per-second output from the board, which is synchronized

Backup battery (V_BAT)

to

GPS time. This is not available in Trickle Power mode

If

not utilized,

it

may be left open.

It

causes the board to reset and start

.

This is the battery backup input that powers the SRAM and RTC when main power is removed.

Typical current draw is 15uA. Without an external backup battery, the module/engine board will

execute a cold star after every turn on. To achieve the faster start-up offered by a hot or warm start,

a battery backup must be connected. The battery voltage should be between 2.0v and 5.0v.

Without an external backup battery or super cap, the TMP will execute a cold start after every power on. To achieve the faster start-up offered by a hot or warm start, either a battery backup must be connected or a super cap installed. To maximize battery lifetime, the battery voltage should not exceed the supply voltage and should be between 2.5V and 3.6V With the super cap (B1) installed, and after at least ten minutes of continuous operation, the data retention is about seven hours. Note that even though all other components are rated at –30 to +85 deg C, a typical super cap is specified over a temperature range of –25 to +70 deg C and a typical rechargeable Lithium battery is over –20 to +70 deg C.

GPIO Functions

Several I/Os are connected to the digital interface connector for custom applications

.

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 Application Circuit

VCC

R1

R2

R3

10k

1 2

RXA TXA TXB

RXB

ET-314

VCC

U1

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15

GPS

VCC GND Bootselect RXA TXA TXB RXB GPIO_14 RF_ON GND A_GND A_GND A_GND A_GND A_GND

GND

1PPS GPIO_15 GPIO_13

GPIO_0 GPIO_5 GPIO_1

GPIO_10

NRESET

V_BAT

VCC_RF

V_ANT

A_GND

RF_IN

A_GND

30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

R4 10k

1 2

BOOT

GPIO_14

1PPS GPIO_15 GPIO_13 GPIO_0 GPIO_5 GPIO_1 GPIO_10 RESET V_BAT VCC_RF V_ANT

50 ohm mic ros t rip line

ACTIVE AN T

2

1

Version 1.2

(1) Ground Planes:

ET-314 GPS receiver needs two different ground planes. The GND_A pin(11、 12、13、14、15、16、18) shall be connect to analog ground. The GND pin(2、

10、30) connect to digital ground.

(2) Serial Interface:

The Serial interface pin(RXA、TX1、TXB、RXB) is recommended to pull up(10KΩ).

It can increase the stability of serial data.

(3) Backup Battery:

It’s recommended to connect a backup battery to V_BAT.

In order to enable the warm and hot start features of the GPS receiver. If you don’t intend to use a

backup battery, connect this pin to GND or open.

If you use backup battery, shall need to add a bypassing capacitor (10uF) at V_bat trace. It can

reduce noise and increase the stability.

(4) Antenna:

Connecting to the antenna has to be routed on the PCB. The transmission line must to controlled

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ET-314

impedance to connect RF_IN to the antenna or antenna connector of your choice.

(5) Active antenna bias voltage:

The Vcc_RF pin (pin 20) is providing voltage 3.3V. If you use active antenna, you can connect this pin

to V_ANT_IN pin (pin 19) to provide bias voltage of active

GPS Active Antenna Specification(Recommendation)

Frequency: 1575.42+2 MHz

Axial Ratio: 3 dB Typical

output Impedance: 50Ω

Polarization: RHCP

Amplifier Gain :20~26dB Typical

Output VSWR: 2.0 Max.

Noise Figure: 2.0 dB Max

Version 1.2

 Dimensions

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 Recommend Layout PAD

ET-314

Version 1.2

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ET-314

n

r

N

m

t

N

p

d

SOFTWARE COMMAND

NMEA Output Command

GGA-Global Positioning System Fixed Data

Table B-2 contains the values for the following example:

$GPGGA,161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M,,,,0000*18

Table B-2 GGA Data Format

Name Example Units Descriptio

Message ID $GPGGA GGA protocol heade UTC Time 161229.487 hhmmss.sss Latitude 3723.2475 ddmm.mmmm

/S Indicator Longitude 12158.3416 dddmm.mmm E/W Indicator W E=east or W=wes Position Fix Indicator 1 See Table B-3 Satellites Used 07 Range 0 to 12 HDOP 1.0 Horizontal Dilution of Precision MSL Altitude1 9.0 meters Units M meters Geoid Separation1 meters Units M meters Age of Diff. Corr. second Diff. Ref. Station ID 0000 Checksum *18 <CR><LF> End of message termination

SiRF Technology Inc. does not support geoid corrections. Values are WGS84 ellipsoid heights.

N=north or S=south

ull fields when DGPS is not used

Version 1.2

Table B-3 Position Fix Indicator

Va l ue D es c ri

0 Fix not available or invali

1 GPS SPS Mode, fix vali

2 Differential GPS, SPS Mode , fix vali

3 GPS PPS Mode, fix vali

tion

GLL-Geographic Position-Latitude/Longitude

Table B-4 contains the values for the following example:

$GPGLL,3723.2475,N,12158.3416,W,161229.487,A*2C

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ET-314

p

r

N

m

t

Table B-4 GLL Data Format

Version 1.2

Name Exam Message ID $GPGLL GLL protocol heade Latitude 3723.2475 ddmm.mmmm

/S Indicator n N=north or S=south Longitude 12158.3416 dddmm.mmm E/W Indicator W E=east or W=wes UTC Position 161229.487 hhmmss.sss Status A A=data valid or V=data not valid Checksum *2C <CR><LF> End of message termination

le Units Description

GSA-GNSS DOP and Active Satellites

Table B-5 contains the values for the following example:

$GPGSA,A,3,07,02,26,27,09,04,15,,,,,,1.8,1.0,1.5*33

Table B-5 GSA Data Format

Name Example Units Description

Message ID $GPGSA GSA protocol header Mode1 A See Table B-6 Mode2 3 See Table B-7 Satellite Used1 07 Sv on Channel 1 Satellite Used1 02 Sv on Channel 2 ….. Satellite Used1 Sv on Channel 12 PDOP 1.8 Position dilution of Precision HDOP 1.0 Horizontal dilution of Precision VDOP 1.5 Vertical dilution of Precision Checksum *33 <CR><LF> End of message termination

1. Satellite used in solution.

Table B-6 Mode1

Va l ue Description

M Manual-forced to operate in 2D or 3D mode A 2Dautomatic-allowed to automatically switch 2D/3D

Table B-7 Mode 2

Va l ue Description

1 Fix Not Available 2 2D 3 3D

GSV-GNSS Satellites in View

Table B-8 contains the values for the following example:

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ET-314

n

r

N

r

)

g

)

g

n

r

N

m

t

yy

t

$GPGSV,2,1,07,07,79,048,42,02,51,062,43,26,36,256,42,27,27,138,42*71

$GPGSV,2,2,07,09,23,313,42,04,19,159,41,15,12,041,42*41

Table B-8 GSV Data Format

Name Example Descriptio

Message ID $GPGSV GSV protocol heade

umber of Messages1 2 Range 1 to 3 Message Numbe Satellites in View 07 Satellite ID 07 Channel 1(Range 1 to 32 Elevation 79 degrees Channel 1(Maximum90 Azimuth 048 degrees Channel 1(True, Range 0 to 359 SNR(C/No) 42 dBHz Range 0 to 99,null when not trackin ……. ……. Satellite ID 27 Channel 4 (Range 1 to 32 Elevation 27 Degrees Channel 4(Maximum90 Azimuth 138 Degrees Channel 4(True, Range 0 to 359 SNR(C/No) 42 dBHz Range 0 to 99,null when not trackin Checksum *71 <CR><LF> End of message termination

Depending on the number of satellites tracked multiple messages of GSV data may be required.

1

1 Range 1 to 3

Version 1.2

RMC-Recommended Minimum Specific GNSS Data

Table B-10 contains the values for the following example:

$GPRMC,161229.487,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,,*10

Table B-10 RMC Data Format

Name Example Units Descriptio

Message ID $GPRMC RMC protocol heade UTC Time 161229.487 hhmmss.sss Status A A=data valid or V=data not valid Latitude 3723.2475 ddmm.mmmm

/S Indicator Longitude 12158.3416 dddmm.mmm E/W Indicator W E=east orW=wes Speed Over Ground 0.13 knots Course Over Ground 309.62 degrees True Date 120598 ddmm Magnetic Variation2 degrees E=east or W=wes Checksum *10 <CR><LF> End of message termination SiRF Technology Inc. does not support magnetic declination. All “course over ground” data are

N=north or S=south

geodetic WGS48 directions.

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ET-314

n

r

g

N

r

p

r

VTG-Course Over Ground and Ground Speed

$GPVTG,309.62,T,,M,0.13,N,0.2,K*6E

Name Example Units Descriptio

Message ID $GPVTG VTG protocol heade Course 309.62 degrees Measured headin Reference T True Course degrees Measured headin Reference M Magnetic Speed 0.13 knots Measured horizontal speed Units Speed 0.2 Km/h Units K Kilometers Checksum *6E <CR><LF> End of message termination

Knots

Measured horizontal speed

er hou

Version 1.2

2.2 NMEA Input Command

A). Set Serial Port ID:100 Set PORTA parameters and protocol

This command message is used to set the protocol(SiRF Binary, NMEA, or USER1) and/or the

communication parameters(baud, data bits, stop bits, parity). Generally,this command would be used to

switch the module back to SiRF Binary protocol mode where a more extensive command message set is

available. For example,to change navigation parameters. When a valid message is received,the parameters

will be stored in battery backed SRAM and then the receiver will restart using the saved parameters.

Format:

$PSRF100,<protocol>,<baud>,<DataBits>,<StopBits>,<Parity>*CKSUM

<protocol> 0=SiRF Binary, 1=NMEA, 4=USER1

<baud> 1200, 2400, 4800, 9600, 19200, 38400

<DataBits> 8,7. Note that SiRF protocol is only valid f8 Data bits

<StopBits> 0,1

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ET-314

<Parity> 0=None, 1=Odd, 2=Even

Example 1: Switch to SiRF Binary protocol at 9600,8,N,1

$PSRF100,0,9600,8,1,0*0C<CR><LF>

Example 2: Switch to User1 protocol at 38400,8,N,1

$PSRF100,4,38400,8,1,0*38<CR><LF>

**Checksum Field: The absolute value calculated by exclusive-OR the 8 data bits of

each character in the Sentence,between, but excluding “$” and “*”. The

hexadecimal value of the most significant and least significant 4 bits of the result are

convertted to two ASCII characters (0-9,A-F) for transmission. The most

significant character is transmitted first.

**<CR><LF> : Hex 0D 0A

Version 1.2

B). Navigation lnitialization ID：101 Parameters required for start

This command is used to initialize the module for a warm start, by providing current position （in X, Y, Z coordinates）,clock offset, and time. This enables the receiver to search for the correct satellite signals at

the correct signal parameters. Correct initialization parameters will enable the receiver to acquire signals

more quickly, and thus, produce a faster navigational solution.

When a valid Navigation Initialization command is received, the receiver will restart using the input

parameters as a basis for satellite selection and acquisition.

Format：

$PSRF101,<X>,<Y>,<Z>,<ClkOffset>,<TimeOfWeek>,<WeekNo>,<chnlCount>,<ResetCfg>

*CKSUM<CR><LF>

<X> X coordinate position

INT32

<Y> Y coordinate position

INT32

<Z> Z coordinate position

INT32

<ClkOffset> Clock offset of the receiver in Hz, Use 0 for last saved

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ET-314

value if available. If this is unavailable, a default value of 75000 for GSP1, 95000 for GSP 1/LX will be used.

INT32

<TimeOf Week> GPS Time Of Week

UINT32

<WeekNo> GPS Week Number UINT16 （ Week No and Time Of Week calculation from UTC time）

<chnlCount> Number of channels to use.1-12. If your CPU throughput

UBYTE

<ResetCfg> bit mask

0×02=clear ephemeris warm start=1

Version 1.2

is not high enough, you could decrease needed throughput by reducing the number of active channels

0×01=Data Valid warm/hotstarts=1

0×04=clear memory. Cold start=1 UBYTE

Example: Start using known position and time. ＄PSRF101,-2686700,-4304200,3851624,96000,497260,921,12,3*7F

C). Set DGPS Port ID:102 Set PORT B parameters for DGPS input

This command is used to control Serial Port B that is an input only serial port

used to receive RTCM differential corrections. Differential receivers may output corrections using different communication parameters. The default communication parameters for PORT B are 9600 Baud, 8data bits, 0 stop bits, and no parity. If a DGPS receiver is used which has different communication parameters, use this command to allow the receiver to correctly decode the data. When a valid message is received, the parameters will be stored in battery backed SRAM and then the receiver will restart using the saved parameters. Format: ＄PSRF102,<Baud>,<DataBits>,<StopBits>,<Parity>*CKSUM<CR><LF> <baud> 1200,2400,4800,9600,19200,38400 <DataBits> 8 <StopBits> 0,1

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<Parity> 0=None,Odd=1,Even=2

Example: Set DGPS Port to be 9600,8,N,1 ＄PSRF102,9600,8,1.0*12

D). Query/Rate Control ID:103 Query standard NMEA message and/or set output rate

This command is used to control the output of standard NMEA message GGA, GLL, GSA,

GSV

RMC, VTG. Using this command message, standard NMEA message may be polled once, or

setup for periodic output. Checksums may also be enabled or disabled depending on the needs of the receiving program. NMEA message settings are saved in battery backed

memory for each entry when the message is accepted. Format: ＄PSRF103,<msg>,<mode>,<rate>,<cksumEnable>*CKSUM<CR><LF> <msg> 0=GGA,1=GLL,2=GSA,3=GSV,4=RMC,5=VTG <mode> 0=SetRate,1=Query

Version 1.2

<rate> Output every <rate>seconds, off=0,max=255

<cksumEnable> 0=disable Checksum,1=Enable checksum for specified

message

Example 1: Query the GGA message with checksum enabled

＄PSRF103,00,01,00,01*25

Example 2: Enable VTG message for a 1Hz constant output with checksum enabled

＄PSRF103,05,00,01,01*20

Example 3: Disable VTG message

＄PSRF103,05,00,00,01*21

E). LLA Navigation lnitialization ID:104 Parameters required to start using

Lat/Lon/Alt This command is used to initialize the module for a warm start, by providing current position (in Latitude, Longitude, Altitude coordinates), clock offset, and time. This enables the receiver to search for the correct satellite signals at the correct signal parameters. Correct initialization parameters will enable the receiver to acquire signals more quickly, and thus, will produce a faster navigational soution. When a valid LLANavigationInitialization command is received,the receiver will restart using the input parameters as a basis for satellite selection and acquisition.

Format:

＄PSRF104,<Lat>,<Lon>,<Alt>,<ClkOffset>,<TimeOfWeek>,<WeekNo>,

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ET-314

<ChannelCount>, <ResetCfg>*CKSUM<CR><LF>

<Lat> Latitude position, assumed positive north of equator and negative

south of equator float, possibly signed

<Lon> Longitude position, it is assumed positive east of Greenwich

and negative west of Greenwich

Float, possibly signed

<Alt> Altitude position

float, possibly signed

<ClkOffset> Clock Offset of the receiver in Hz, use 0 for last saved value if

available. If this is unavailable, a default value of 75000 for GSP1,

95000 for GSP1/LX will be used. INT32 <TimeOfWeek> GPS Time Of Week UINT32 <WeekNo> GPS Week Number

Version 1.2

UINT16 <ChannelCount> Number of channels to use. 1-12

UBYTE

<ResetCfg> bit mask 0×01=Data Valid warm/hot starts=1 0×02=clear ephemeris warm start=1 0×04=clear memory. Cold start=1

UBYTE Example: Start using known position and time.

＄PSRF104,37.3875111,-121.97232,0,96000,237759,922,12,3*37

F). Development Data On/Off ID:105 Switch Development Data Messages On/Off Use this command to enable development debug information if you are having trouble getting commands accepted. Invalid commands will generate debug information that should enable the user to determine the source of the command rejection. Common reasons for input command rejection are invalid checksum or parameter out of specified range. This setting is not preserved across a module reset. Format: ＄PSRF105,<debug>*CKSUM<CR><LF>

<debug> 0=Off,1=On Example: Debug On ＄PSRF105,1*3E Example: Debug Off ＄PSRF105,0*3F

G). Select Datum ID:106 Selection of datum to be used for coordinate Transformations

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GPS receivers perform initial position and velocity calculations using an earth-centered earth-fixed

(ECEF) coordinate system. Results may be converted to an earth model (geoid) defined by the

selected datum. The default datum is WGS 84 (World Geodetic System 1984) which provides a

worldwide common grid system that may be translated into local coordinate systems or map datums.

(Local map datums are a best fit to the local shape of the earth and not valid worldwide.)

Examples:

Datum select TOKYO_MEAN

$PSRF106,178*32

ET-314

Version 1.2

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