FALCOM JP7-T Series Guide

This document is available at HTTP://WWW.FALCOM.DE/ .
JP7-T Family
GPS-Receiver
Hardware description
Version 1.02

GPS-RECEIVER JP7-T VERSION 1.02
Contents
0INTRODUCTION ..............................................................5
0.1 GENERAL........................................................................................................................................ 5
0.2 SCOPE OF THE USER’S MANUAL ...................................................................................................... 6
0.3 USED ABBREVIATIONS.................................................................................................................... 7
0.4 RELATED DOCUMENTS.................................................................................................................... 7
0.5 ORDER OPTIONS.............................................................................................................................. 8
1SECURITY .........................................................................9
1.1 GENERAL INFORMATION................................................................................................................. 9
1.2 RESTRICTED USE............................................................................................................................. 9
1.3 CHILDREN ...................................................................................................................................... 9
1.4 OPERATION/ANTENNA .................................................................................................................... 9
1.5 ELECTROSTATIC DISCHARGE (ESD)............................................................................................. 10
2SAFETY STANDARDS ...................................................11
3GPS BASICS PRINCIPLE ..............................................12
3.1 SIGNAL PROCESSING OPERATION ................................................................................................. 12
4TECHNICAL DATA........................................................13
5DESCRIPTION OF OPERATING MODES .................15
5.1 NORMAL OPERATION ................................................................................................................... 15
5.2 TRICKLE POWER OPERATION ....................................................................................................... 15
5.3 PUSH-TO-FIX MODE ..................................................................................................................... 16
5.4 NMEA INPUT MESSAGE FOR TRICKLE POWER MODE................................................................... 16
6TECHNICAL DESCRIPTION .......................................19
6.1 RECEIVER ARCHITECTURE ........................................................................................................... 19
6.2 DESCRIPTION OF GPS RECEIVING SIGNALS................................................................................... 20
6.3 START-UP MODES ........................................................................................................................ 20
6.3.1 Cold start...................................................................................................................................... 20
6.3.2 Warm start ................................................................................................................................... 21
6.3.3 Hot start ....................................................................................................................................... 21
6.4 PRODUCT APPLICATIONS .............................................................................................................. 21
6.5 TECHNICAL SPECIFICATIONS......................................................................................................... 22
6.5.1 Electrical Characteristics ............................................................................................................. 22
6.6 HARDWARE INTERFACE ................................................................................................................ 24
6.7 BALLS ASSIGNMENT OF THE JP7-TB............................................................................................. 25
6.8 PIN ASSIGNMENT OF THE 50-PIN CONNECTOR ............................................................................... 28
6.8.1 Configuration and timing signals................................................................................................. 30
6.8.2 Serial communication signals ...................................................................................................... 31
6.8.3 DC input signals .......................................................................................................................... 32
6.8.4 General purpose input/output....................................................................................................... 33
7SOFTWARE INTERFACE.............................................34
7.1 SIRF BINARY DATA MESSAGE....................................................................................................... 34
7.2 NMEA DATA MESSAGE ................................................................................................................ 36
7.2.1 NMEA output messages .............................................................................................................. 37
7.2.2 NMEA input messages ................................................................................................................ 37
7.2.3 Transport Message....................................................................................................................... 38
8MECHANICAL DRAW ..................................................39
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 2

GPS-RECEIVER JP7-T VERSION 1.02
9LAYOUT RECOMMENDATION..................................42
9.1 GROUND PLANES .......................................................................................................................... 42
9.2 RF CONNECTION........................................................................................................................... 42
10 FIRST STEPS TO MAKE IT WORK............................45
11 APPENDIX .......................................................................48
11.1 BOARD-TO-BOARD CONNECTOR ................................................................................................... 48
11.2 RF CONNECTOR............................................................................................................................ 48
11.3 FIRMWARE INTERFACE ................................................................................................................. 49
11.4 XTRAC FIRMWARE DESCRIPTION .................................................................................................. 49
11.4.1 SiRFXTrac2 firmware default settings ........................................................................................ 49
11.4.2 Order options ............................................................................................................................... 50
Version history
Version number Author Changes
1.00 Fadil Beqiri Initial version
1.01 Fadil Beqiri - The signal names of serial ports updated
- New section 11.4 “XTrac software
description” added.
- CheckSum calculation added
- A complete update implemented.
1.02 Fadil Beqiri - Chapter 11.3 updated.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 3

GPS-RECEIVER JP7-T VERSION 1.02
Cautions
Information furnished herein by FALCOM is believed to be accurate
and reliable. However, no responsibility is assumed for its use. Also
the information contained herein is subject to change without notice.
Please, read carefully the safety precautions.
If you have any technical questions regarding this document or the
product described in it, please contact your vendor.
General information about FALCOM and its range of products is
available at the following internet address: http://www.falcom.de/
Trademarks
Some mentioned products are registered trademarks of their respective
companies.
Copyright
The JP7-T family hardware description and user’s guide are
copyrighted by FALCOM GmbH with all rights reserved. No part of
this user’s guide may be produced in any form without the prior
written permission of FALCOM GmbH.
FALCOM GmbH.
No patent liability is assumed with respect to the use of the information
contained herein.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 4

GPS-RECEIVER JP7-T VERSION 1.02
0 Introduction
0.1 General
This description is focussed on the GPS receiver of the FALCOM JP7-T
family from FALCOM GmbH. The JP7-T family is an excellent device
designed and supports a wide variety of solutions regarding to the customer
fulfilment, the wide variety of the JP7-T family offers easy integration in the
various way on the user independent application platform. Regarding to the
JP7-T family (which contains JP7-T, JP7-TB, JP7-TC-1(-2)) concept, there
are three different GPS receiver with different options. This manual contains
information about purpose and use of the GPS receivers included into the
FALCOM JP7-T family. Please read this manual very carefully to avoid any
mistakes and to secure an optimal use of the devices. Each GPS receiver
into the JP7-T family is a single-board 12 parallel channel receiver intended
as a component for OEM products. The FALCOM JP7-T family is based
and advanced on the Falcom JP7 GPS receiver which delivers major
advancement in GPS performance, accuracy, integration, computing power
and flexibility without modification regarding to the receiver form factor
and pin-out. Each GPS receiver of the FALCOM JP7-T family has an
integrated temperature compensated crystal oscillators (TCXO). Due to the
higher stability of frequency it offers a high improved performance.
Additionally, a TCXO accept the condition for use the SiRFXTrac2
firmware. The JP7- T family using SiRFXTrac2 firmware is able to track
the GPS signals an extremely small level by 16 dBHz. In addition, higher
sensitivity allows it more flexibility on the its design, the placement of the
antenna and the selection of the kind of antenna. The GPS receiver
continuously tracks all satellites in view, thus providing accurate satellite
position data. The highly integrated digital receiver uses the SiRFstarII-Low
Power chipset. The internal GPS software completes the package providing
flexible system architecture for standalone GPS based products.
In order to save space on the application platform, the Falcom JP7-T family
comes as an extremely slim and compact module. This makes it ideally
suited for a broad range of mobile computing devices, and particularly
offers easy integration with smart phones, PDAs, and other handhelds.
The FALCOM JP7-T family is also designed to be an entire product such as
an AVL tracking unit, handheld GPS.
Please consult SiRF (www.sirf.com) for special information about the
SiRFstarII-Low Power chipset.
Figure 1: The FALCOM JP7-T family GPS receiver (top, side and bottom view)
Users are advised to proceed quickly to the chapter "Security" and read the
hints carefully to secure its optimal use.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 5

GPS-RECEIVER JP7-T VERSION 1.02
0.2 Scope of the user’s manual
This document describes the hardware interface and the technical
specifications of the JP7-T.
It is also the preliminary data sheet for the electrical and mechanical device
application design.
As far as JP7-T family concept is concerned, there are three different JP7-T
GPS Receiver Modules available. The difference between these receivers
can be recognised by looking on the bottom side of the module (see attached
picture on the chapter 0.5 “Order option”).
To choose a unit it depends on the customer requirements:
JP7-T JP7-TB JP7-TC-1 JP7-TC-2
RF Part
TCXO 25.5535 MHz 25.5535 MHz 25.5535 MHz 25.5535 MHz
Active
antenna power
control
built in built in built in built in
RF connector Not available Not available
U.FL-R-SMT –
plug antenna
connector from
Hirose.
No RF
connector.
Solder pads, only
Digital Part
Connector Not available Not available
50-pin, Hirose
DF12C, Board-To-
Board connector
50-pin, Hirose
DF12C, Board-
To-Board
connector
Balls Not available 48-Balls are
available Not available Not available
In this manual user will not find separately description for each option of
devices. The interfaces, pin-out and some application’s example are the
same for all devices.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 6

GPS-RECEIVER JP7-T VERSION 1.02
0.3 Used abbreviations
Abbreviation Description
DGPS Differential GPS
DOP Dilution of Precision
GPS Global Positioning System
GGA GPS Fixed Data
LNA Low Noise Amplifier
NMEA National Maritime Electronics Association
PRN Pseudo - Random Noise Number – The Identity of GPS satellites
RF Radio Frequency
RP Receive Protocol
RTC Real Time Clock
RTCM Radio Technical Commission for Maritime Services
SDI Data input
SDO Data output
SA Selective Availability
WAAS Wide Area Augmentation System
MSK Minimum Shift Keying
PCB Printed Circuit Board
PRN Pseudo-random noise
IF Intermediate Frequency
A/D Analog/Digital
0.4 Related documents
[1.] SiRF binary and NMEA protocol specification;
http://www.falcom.de/service/downloads/manual/SiRF/SiRFmessages.pdf
[2.] SiRF-demo software and manual;
http://www.falcom.de/service/downloads/manual/SiRF/SiRFdemo.pdf
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 7
http://www.falcom.de/service/downloads/manual/SiRF/SiRFdemo.zip

GPS-RECEIVER JP7-T VERSION 1.02
0.5 Order options
Before you start up the receiver, make sure that your package includes the
following items. If any item is missing or damaged, please contact your
vendor immediately. According to your requirements you can choose the
desired unit. In the figure below the available components are marked with
red colour. (In order to have a clearly view and to detect the required option
of JP7-T family imaged below, please print this page with a colour printer.)
The table below contains the order options of JP7-T family.
Name Options
JP7-T 30-pin out on the left and right side of JP7-T are available for use
JP7-TB 48 Balls are available for use
JP7-TC-1 A 50-pin connector and a RF connector are
available for use
JP7-TC
JP7-TC-2
A 50-pin connector and solder pads for an antenna
cable are available for use.
There is no antenna cable included in the delivery
package.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 8

GPS-RECEIVER JP7-T VERSION 1.02
1 Security
This chapter contains important information for the safe and reliable use of
the GPS receiver. Please read this chapter carefully before starting to use the
GPS receiver.
1.1 General information
The Global Positioning System uses satellite navigation, an entirely new
concept in navigation. GPS has become established in many areas, for
example, in civil aviation or deep-sea shipping. It is making deep inroads in
vehicle manufacturing and before long everyone of us will use it this way or
another.
The GPS system is operated by the government of the United States of
America, which also has sole responsibility for the accuracy and
maintenance of the system. The system is constantly being improved and
may entail modifications effecting the accuracy and performance of the GPS
equipment.
1.2 Restricted use
Certain restrictions on the use of the GPS receiver may have to be observed
on board a plane, in hospitals, public places or government institutions,
laboratories etc. Follow these instructions.
1.3 Children
Do not allow children to play with the GPS receiver. It is not a toy and
children could hurt themselves or others. The GPS receiver consists of many
small parts which can come loose and could be swallowed by small
children. Thoughtless handling can damage the GPS receiver.
1.4 Operation/antenna
Operate the GPS receiver with an antenna connected to it and with no
obstruction between the receiver and the satellite.
Make absolutely sure that the antenna socket or antenna cable is not shorted
as this would render the GPS receiver disfunctional.
Do not use the receiver with a damaged antenna. Replace a damaged
antenna without delay. Use only a manufacturer-approved antenna. Use only
the supplied or an approved antenna with your GPS receiver. Antennas from
other manufacturers which are not authorized by the supplier can damage
the GPS receiver.
Technical modifications and additions may contravene local radio-
frequency emission regulations or invalidate the type approval.
Authorized GPS antennas:
FAL-ANT-3 (active antenna)
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 9

GPS-RECEIVER JP7-T VERSION 1.02
1.5 Electrostatic Discharge (ESD)
The JP7-T family GPS receiver contains class 1 devices. The following
Electrostatic Discharge (ESD) precautions are recommended:
- Protective outer garments.
- Handle device in ESD safeguarded work area.
- Transport device in ESD shielded containers.
- Monitor and test all ESD protection equipment.
- Treat the JP7-T family GPS receiver as extremely sensitive to ESD.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 10

GPS-RECEIVER JP7-T VERSION 1.02
2 Safety standards
The GPS receiver meets the safety standards for RF receivers and the
standards and recommendations for the protection of public exposure to RF
electromagnetic energy established by government bodies and professional
organizations, such as directives of the European Community, Directorate
General V in matters of radio frequency electromagnetic energy.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 11

GPS-RECEIVER JP7-T VERSION 1.02
3 GPS basics principle
3.1 Signal Processing Operation
The JP7-T family is designed to use L1 Frequency (C/A Code). The module
is separated into four major parts: RF frequency down-converter, digital
baseband demodulation, embedded ARM microprocessor and internal
GPS software stored on-board (8 MBits) Flash-Memory. The RF frequency
conversion and the baseband demodulation are executed by hardware while
the embedded ARM processor computes the GPS Position, Velocity and
Time solution employing the internal GPS software.
♦ The purpose of the RF circuitry is to reinforce the very weak (-
130dBm nominal) GPS signal, filters it and down-converts it to an
Intermediate Frequency (IF) of 9.45MHz for digital processing. The
JP7-T family architecture relies on the high level of integration in the
RF part to significantly reduce part count and circuit complexity. The
IF filter is built-in as well.
♦ The digital baseband demodulator takes the quantified GPS signal and
detects the individual satellites serial data bit stream, along with the
associated pseudo range. This action consists of removing spread
spectrum and Doppler frequency components of the signal to obtain
the serial data messages.
♦ The embedded ARM processor monitors channel allocation, extracts
the raw satellite tracking data, computes the position and time solution
and sends it on a serial port for high level applications to use or
process it locally. Support functions for the microprocessor include
real-time clock and reset pulse generator circuits.
♦ The internal GPS software monitors and allocate channels, computes
the Position, Velocity and Time using the pseudo-range of the
satellites and reformat the data to be output at the serial interface or
used locally. The internal GPS software is a tasking based architecture
driven by the 100ms interrupt generated by GSP2e internal hardware.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 12

GPS-RECEIVER JP7-T VERSION 1.02
4 Technical data
FEATURES
- OEM single board 12 channel GPS receiver
- size: JP7-T : 25,4 x 25,4 x 3 mm (L x B x H)
JP7-TB : 25,4 x 25,4 x 3.3 mm (L x B x H)
JP7-TC-1 : 25,4 x 25,4 x 5.2 mm (L x B x H)
JP7-TC-2 : 25,4 x 25,4 x 5.2 mm (L x B x H)
- weight: JP7-T : 2,5 g (without shielding)
JP7-TB : 2,5 g (without shielding)
JP7-TC-1 : 2,5 g (without shielding)
JP7-TC-2 : 2,5 g (without shielding)
- Casing: Fully shielded
- TCXO
- 8Mbit FLASH memory
- operating voltage: +3.3 V DC ±5 %
- power consumption: 220 mW (continuous mode with Low
Power chipset)
- temperature range: -40 to +85 °C (operation, transportation
and storage)
- protocol: SDI1/ SDO1:
NMEA 9600 baud, Msg.: GLL, GGA,
RMC, VTG, GSV, GSA
8 data bits, no parity, 1 stop bit
SDI2/ SDO2:
RTCM, 9600 baud
- trickle power mode: The default Mode of FALCOM JP7-T is
continuous Mode, but the user can set
FALCOM JP7-T into the Trickle Power
Mode via input command message. The
FALCOM JP7-T family enters the trickle
power mode corresponding to figure 2 (800
ms OFF Time and 200 ms ON Time) as soon as
valid GPS data are available. As a result the
average power consumption is reduced by
approximately 80 % (approximately 150
mW). The settings for the trickle power
mode can be modified by using the SiRFstar
demo software. For example if the FALCOM
JP7-T is configured to enter the OnTime
mode each 10 s for a duration of 200 ms the
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 13

GPS-RECEIVER JP7-T VERSION 1.02
average power consumption can be reduced
up to approx. 95 % (approx. 15 mW, ca. 4,8
mA at Vcc=3.3 V).
For more details see chapter 4 “Operating
modes”.
Figure 2: Example for the trickle power mode of FALCOM JP7-T family
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 14

GPS-RECEIVER JP7-T VERSION 1.02
5 Description of operating modes
There are three basic operating in which the JP7-T family operates during
use. Each mode is used to accomplish a different task during the process of
acquiring and maintaining the GPS information. The Falcom JP7-T family
designs include all the functionality necessary to implement the three
different modes of operation. The default mode of JP7-T family is normal
mode (continuous mode). Three different operating modes are described
below. Additionally, two of them are designed as low-power mode
consumption such as the Trickle Power mode and Push-To-Fix mode.
5.1 Normal Operation
In this default implementation of normal mode the JP7-T family is fully
powered and performs the function of signal search, acquisition,
measurement and satellite tracking. The amount of time spent in the initial
full power is dependent on the start condition that applies the number of
satellites for which the ephemeris must be collected and the time to calibrate
the RTC as well as the location of the GPS antenna (which it must have an
unobstructed view to the sky in order to receive the satellite radio
transmissions). When the JP7-T family has been locked-on to at least four
satellites, the receiver is able to calculate its current positions. In this mode
the JP7-T family is fully powered and satellite searching, initial acquisition,
initial position calculation and tracking measurements functions are always
performed. In order to reduce the start up time of the receiver it is preferable
to be connected to an external back up battery, so that the RTC is running
during the power interrupt. The backup power is required for retention of
SRAM memory and maintaining the Real-Time-Clock. The validity of data
stored in SRAM is kept due to RTC keeps running and these data will be
needed on the next power up scenario.
5.2 Trickle Power Operation
In the Trickle Power mode, power is still applied to the JP7-T family, but
the GPS engine is shut off and RF circuits are powered down. The Trickle
Power mode provides a method of operating the JP7-T family in a user
programmable duty cycle, consisting of a receiver measurement on time
tracking and an interval of position update, thereby reducing the average
power consumption over a period of time. The transition into the Trickle
Power mode of JP7-T family can be implemented and configured by using
the Set Operating Mode command in SiRFdemo. Between two on time
tracking periods the JP7-T family sets itself in the sleep phase in other word
into the low power consumption. The transition from sleep mode of JP7-T
family back to the on time tracking is generated through the internal RTC
which transmits a wakeup signal to the GPS engine to switch it on as well
the RF circuit is powered on. The JP7-T is waked up and begins to acquire
the on view satellites. In order to reduce the start up time of the receiver for
the next power up is preferable to connect an external back up battery, so
that the RTC is running during the power interrupt and the required data and
the Trickle Mode configuration are kept from previous operation. If the
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 15

GPS-RECEIVER JP7-T VERSION 1.02
receiver fails to acquire satellites within a given period of time (approx. 150
sec), the receiver sets itself into the sleep phase. The duration of this sleep
phase is approx. 30 sec. After that, the receiver wakes up, reset itself and
tries to acquire satellites which are in view. This procedure repeats itself
until the initial position computation of GPS receiver is completed.
Hint: After initial turn on or system reset, the JP7-T will remain in the
full power tracking until a series of Kalman filter navigation
solution is obtained, all ephemeris data is collected and the RTC is
calibrated prior to transitioning to the low power duty cycle mode.
5.3 Push-to-Fix Mode
The Push-to-Fix mode puts the FALCOM JP7-T family into a background
duty cycle which provides a periodic refresh of position, receiver time,
ephemeris data and RTC calibration every 30 minutes. The Push-to-Fix
mode is similar but executive from Trickle Power mode, meaning that only
one mode can be set at a time. In this mode the receiver sets itself into the
sleep phase for 29.5 minutes and a full tracking phase for 30 seconds.
During the tracking phase the JP7-T family acquires satellites, computes
position and updates ephemeris data as well the RTC is being calibrated.
The transition into the Push-to-Fix mode of JP7-T family can be
implemented and configured by using the Set Operating Mode command
in SiRFdemo. During the subsequent background cycles or when a user
requests a position update (the RESET_N has to be used) a reset is
generated and a hot start will be typically performed which may take up to a
maximum of 8 seconds. The receiver wakes up, computes its position fix
and goes back to the previous sleep phase again.
5.4 NMEA input message for Trickle Power Mode
The input command message below sets the FALCOM JP7-T family into
the Trickle Power Mode or Push-To-Fix Mode. Details to configure Trickle
Power Mode and Push-To-Fix Modes are described below.
The receiver accepts the input message with following format:
$PSRF107,<parameter>, <parameter> ,<parameter><* Checksum><CR> <LF>.
COMAND
SYNTAX DESCRIPTION
$PSRF107,
ptf,
dc,
msot
*XX
<CR><LF>
Parameters description:
ptf // numeric, performs the receiver in one of two pre-defined modes
Possible values:
0: Set the receiver in Trickle Power mode
1: Set the receiver in Push-To-Fix mode
dc // numeric, Duty Cycle in percent (%)
Possible value:
max 1000: Set the time which will be spent for tracking (dc% / 10)
msot // numeric, the on Time in milliseconds
Possible value
200.. 900: Set the time duration of each tracking period
*XX // Checksum has to be calculated in hexadecimal.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 16

GPS-RECEIVER JP7-T VERSION 1.02
Example:
$PSRF107,0,200,200*3D
The receiver will be set in Trickle Power mode where 20% of time it will spend for
tracking and the tracking period will takes 200 msec.
Table 1: Example of Trickle Power Mode Control.
Note:
If the receiver is set into the Trickle Power Mode, the high data rate
transmission is recommend as suitable.
Computation of Duty Cycle and On Time
The Duty Cycle is the desired time, which will be spent for tracking. The
On Time is the duration of each tracking period (range is 200 - 900 msec.)
To calculate the Trickle Power update rate as a function of Duty Cycle and
On Time, use the following formula:
On Time – (Duty Cycle * On Time)
Off Time = ---------------------------------------------
Duty Cycle
Update rate = Off Time + On Time
Hint:
It is not possible to enter an On Time > 900 msec.
Following are some examples of selections:
Mode On Time (msec) Duty Cycle (%) Update Rate (1/Hz)
Continuous 1000 100 1
Trickle Power 200 20 1
Trickle Power 200 10 2
Trickle Power 300 10 3
Trickle Power 500 5 10
Table 2: Example of Selections for Trickle Power Mode of Operation.
Update Rates (seconds)
On Time
(msec) 1 2 3 4 5 6 7 8 9 10
200 √√√√√√√√√√
300 √√√√√√√√√√
400 √√√√√√√√√√
500 √√√√√√√√√√
600 √√√√√√√√√√
700 √√√√√√√√√
800 √√√√√√√√√
900 √√√√√√√√√
Table 3: Trickle Power supported Modes.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 17

GPS-RECEIVER JP7-T VERSION 1.02
Push-To-Fix
In this mode the receiver will turn on every 30 minutes to perform a system
update consisting of a RTC calibration and satellite ephemeris data
collection if required (i.e., a new satellite has become visible) as well as all
software tasks to support SnapStart in the event of an NMEA. Ephemeris
collection time in general takes 18 to 30 seconds If ephemeris data is not
required then the system will re-calibrate and shut down. In either case, the
amount of time the receiver remains off will be in proportion to how long it
stayed on:
On Period * (1-Duty Cycle)
Off period = ---------------------------------------------
Duty Cycle
The off period has a possible range between 10 and 7200 seconds. The
default is 1800 seconds.
Comparison
A comparison of the Trickle Power and Push-to-Fix modes is shown in
Figure below. This diagram shows that for position update intervals less
than approximately 600 seconds (i.e. rates faster than one fix per 10
minutes), the Trickle Power mode at an update interval of 10 seconds offers
a lower power solution. The user would then be required to filter the output
position data to use only the data points corresponding to the desired update
interval. For example, if the desired position output is at 60 second intervals,
then the user would only need one out of every six position outputs at a 10
second Trickle Power update interval. Alternatively, the user could perform
smoothing or averaging of the position data and provide an output at the
desired rate.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 18

GPS-RECEIVER JP7-T VERSION 1.02
6 Technical Description
6.1 Receiver Architecture
The JP7-T family OEM GPS receiver from FALCOM is new OEM GPS
receiver product that features the SiRFstarII-Low Power chipset. This
completes 12 channel, WAAS-enabled GPS receiver provides a vastly
superior position accuracy performance in a much smaller package. The
SiRFstarII architecture builds on the high-performance SiRFstarI core,
adding an acquisition accelerator, differential GPS processor, multipath
mitigation hardware and satellite-tracking engine. The JP7-T family delivers
major advancements in GPS performance, accuracy, integration, computing
power and flexibility.
Figure 3: Receiver architecture of the JP7-T family GPS receiver.
Figure 3 above shows the block diagram of the JP7-T family architecture.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 19

GPS-RECEIVER JP7-T VERSION 1.02
6.2 Description of GPS receiving signals
When the GPS receiver is initially turned on, it begins to determinate its
current positions, velocity and time. In order to perform a successful start it
must have a current almanac, a reasonable expectation of its current location
and a reasonable idea of the current time. When the Ephemeris data are
completely collected, then satellite signals are tracked continuously and the
position is calculated from time to time.
While the receiver trying to obtain a position fix, it needs to be locked-on to
at least four satellites. In order to calculate quickly its current location, the
receiver uses the current received signals, together with data from its
memory (SRAM).
The initial state of the receiver refers to the last status of the receiver in
memory (SRAM). This essentially determines the length of time it will take
for the receiver to obtain a GPS fix. Position can be quickly fixed within 8
seconds from a "hot-start" state, and typically 45 seconds from a "cold-start"
state.
The receiver uses the satellite signals to calculate its exact current location
by calculating the receiver distance from the satellites. The position data
within the receiver is then converted into latitude and longitude coordinates,
which are usually provided in the geodetic datum on which the GPS is based
(WGS84).
6.3 Start-Up Modes
The start-up modes of the JP7-T family depend on the last stored position in
the SRAM memory, such as the current time and ephemeris data. So that the
JP7-T family can be initiated to one of three different start up procedures,
but note that only one can be initiated at a time. In order to perform a Warm
and Hot start, a backup battery has to be connected to the JP7-T family.
Without an external backup battery the receiver will perform a cold start
after every turn on. To achieve the faster start-up offered by a hot or warm
start, a backup battery must be connected. To maximize battery lifetime, the
battery voltage should not exceed the maximal supply voltage and should be
between 2.85 V and 3.15 V.
6.3.1 Cold start
The unit stores data about where the satellites are located at any given time.
The data is called almanac. Occasionally, when the JP7-T family has been
turned off for a long time, the almanac can get out-dated or “cold”. The cold
start takes place when the receiver does not know its last position or time. In
this start-up mode, the receiver either does not operate under back-up power
conditions or it is the first start-up time (i.e. no idea about ephemeris or
almanac data). At this time, the Ephemeris data has yet to be completely
collected. Once the ephemeris data is collected from in view satellites, then
the data from these satellites is considered valid and available for
navigation. This start up scenario is one of the longest time which the
receiver will take to obtain a GPS fix.
This confidential document is the property of FALCOM GmbH and may not be copied or circulated without permission.
Page 20