User manual HAICOM HI-204III

[. . . ] Using the receiver, you can determine your location with great precision. The satellites are positioned so that we can receive signals from six of them nearly 100 percent of the time at any point on Earth. Satellites are equipped with very precise clocks that keep accurate time to within three nanoseconds- that's 0. 000000003, or three billionths of a second. This precision timing is important because the receiver must determine exactly how long it take s for signals to travel from each GPS satellite. [. . . ] Tracking sensitivity of -159dBm offers good navigation performance even in urban canyons having limited sky view. 8 Satellite-based augmentation systems, such as WAAS and EGNOS, are supported to yield improved accuracy. Both the LVTTL-level and RS232-level serial interface are provided on the interface connector. Supply voltage of 3. 3V, or 3. 8V~12V are supported. 1. 2 Features · 20 parallel channel GPS receiver · 4000 simultaneous time-frequency search bins · SBAS (WAAS, EGNOS) support · -159dBm tracking sensitivity · < 8 second hot start · < 40 second cold start 9 SECTION 2 RECEIVER OPERATION Upon power up, after initial self-test has completed, the HI-204III will begin satellite acquisition and tracking process. Under normal open-sky condition, position-fix can be achieved within approximately 35 seconds (within 10 seconds if valid ephemeris data is already collected from recent use). After receiver position has been calculated, valid position, velocity and time information are transmitted through the on board serial interface. The receiver uses the latest stored position, satellite data, and current RTC time to achieve rapid GPS signal acquisition and fast TTFF. If the receiver is transported over a large distance across the globe, cold-start automaticlocate sequence is invoked. The first position fix may take up to 50 sec searching the sky for the GPS signal. The acquisition performance can be improved significantly if the host initializes the receiver with a rough estimate of time and user position. 10 As soon as GPS signal is acquired and tracked, the HI-204III will transmit valid navigation information through its serial interface. The navigation data contains following information: · Receiver position in latitude, longitude, and altitude · Receiver velocity · Time · DOP error-magnification factor · GPS signal tracking status The HI-204III will perform 3D navigation when four or more satellites are tracked. When three or fewer satellites are tracked, altitude-hold is enabled using the last computed altitude and 2D navigation mode is entered. With signal blockage or rising and setting of the satellites, where a change in satellite constellation used for position fix occurred, large position error may result. The HI-204III incorporates a proprietary algorithm to compensate the effect of satellite constellation change, and maintains an accurate smooth estimate of the receiver position, velocity, and heading. 11 2. Electrical Characteristics Chipset General Items GSP3F Frequency C/A code Channels Position Accuracy Velocity Time Default Other Reacquisition Snap start Hot start Warm start Cold start Altitude Velocity Acceleration Jerk Main power input Description SiRF StarIII technology L1, 1575. 42 MHz 1. 023 MHz chip rate 20 10 meters, 2D RMS 5 meters 2D RMS, WAAS corrected <5meters(50%), DGPS corrected 0. 1 meters/second 1 microsecond synchronized to GPS time WGS-84 selectable for other Datum 0. 1 sec. , average 1 sec. , average 8 sec. , average 38 sec. , average 42 sec. , average 18, 000 meters (60, 000 feet) max. 5V DC input. Datum Acquisition Rate (Open Sky & Stationary Requirements) Dynamic Conditions Power Dimension Weight Power consumption 0. 38 W (continuous mode) Supply Current 75mA Backup power 3 V Lithium-Ion rechargeable battery 43mm L x 42mm W x 13mm H 23g 2. 2 LED INDICATOR LED flashing 0. 25Hz LED flashing 1Hz Signal Searching Position Fixed 12 SECTION 3 HARDWARE INTERFACE 3. 1 MECHANICAL DIMENSIONS Unit:mm Top View 69±0. 2 I/O Cable Build-in patch antenna Lateral View 20±0. 2 I/O Cable Bottom View LED indicator 69±0. 2 I/O Cable CPU Magnetic 73±0. 2 13 3. 2 ONE-PULSE-PER-SECOND (1PPS) OUTPUT The one-pulse-per-second output is provided for applications requiring precise timing measurements. Rising edge of the output pulse is accurate to +/-1usec with respect to the start of each GPS second. Accuracy of the one-pulse-per-second output is maintained only when the GPS receiver has valid position fix. The 1PPS output is always generated when the GPS receiver is powered-on. Proper adjustment of the 1PPS output to align with the GPS second requires calculation of the receiver clock offset and clock drift-rate as part of the position-velocity-time (PVT) solution. When enough satellite signals are received to generate valid position fixes, the 1PPS output is adjusted to align with the GPS second in several seconds. [. . . ] Checksum ON Baud Rate: Elevation Mask: DOP Mask: 4800 Baud 5 degrees DOP Select: Auto GDOP: 10 PDOP: 10 HDOP: 10 Normal Mode (without 1PPS) output) output) output) output) Receiver Operating Mode: Commands can be issued to the HI-204III to change the settings of the receiver. The new settings will remain effective on next power-on as long as the on-board rechargeable backup battery is not discharged. After the backup battery is discharged, factory preset default settings will be used. 24 TROUBLESHOOTING Problem No Position output but timer is counting Reasons Weak or no GPS signal can be received at the place of HI-204III unit At outdoor space but GPS signal is blocked by building or car roof Solutions Place the HI-204III under an open space, then, press 'Reset' To try again, go to outdoor and press 'Reset' or connect external antenna on the side of HI-204III to improve the poor GPS signal PocketPC support multiple typs of CPU. You can use the PDA smart menu's 'setting' function to see wether the CPU type is correct or not. [. . . ]