北京合众思壮科技有限责任公司乔任梁死亡真相
January 5, 2006 Version 1.0
目 录
1适用范围 (2)
2启动时间定义 (2)
2.1U-BLOX (2)
2.2GE1100 (5)
2.3U N AV (6)
3NMEA-0183 错误！未定义书签。4RTCM (8)
5地理坐标系索引表 (9)
1适用范围
萧湘溪苑本说明所适用和涉及的范围，仅针对 GPS接收模块产品。
2 启动时间定义
2.1 u-blox
Depending on the receiver’s knowledge of last position, current time and ephemeris Data, the receiver will apply different strategies to start-up, namely:
Coldstart
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In Coldstart, the receiver has no knowledge of its last position or time. This is the ca when the RTC has not been running, no valid ephemeris data or almanac data is available (This is the ca if the receiver has never been navigating or the battery backup memory is lost).
Warmstart
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Warmstart is performed whenever the receiver has only access to valid almanac data, and has not significantly moved since the last valid position calculation. This is typically the ca, if the receiver has been shut off for more than 2 hours, but still has knowledge of last position, time and almanac. T
his allows it to predict the current visible SVs. However, since ephemeris data is not available or outdated, the receiver needs to wait for the ephemeris broadcast to complete.
Hotstart
Hotstart is performed whenever the receiver still has access to valid ephemeris data and preci time. This is typically the ca if the receiver has been shut off for less than 2 hours and the RTC has been running during that time. Furthermore, during the previous ssion, the receiver must have been navigating (to allow it to decode and store ephemeris data). In Hotstart, the receiver can predict the currently visible SVs, and is therefore able to quickly acquire and track the signal. Becau ephemeris is already known, there is no need to wait for the ephemeris broadcast to complete.
2.2 ATMEL
Cold Start: At system start-up, the system has no information about last position and current time.
Plea note that some competitors may not do a cold start even when
pressing the appropriate button / command to do so, so the backup
5岁儿童身高supply has to be removed to force them to do a “real” cold start. Warm start: At system start-up:
·the last position is known
·the current time is known
沛谙·the almanac data are valid
·The ephemeris are not available or outdated (older than 4hrs).
Hot start: At system start-up:
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·the last position is known,
·the current time is known,
·
the almanac data are valid,
·the ephemeris data are valid.
At hot and warm start, the data are stored in the backup memory.
2.3 GE1100旺旺狗
Acquisition Time (TTFF)
The acquisition test is best carried out by allowing the receiver to establish a position fix and then download a full almanac and ephemeris databa, which may take up to 1 minute. The acquisition tests can then be carried out in the following order.
Hot Start
A Hot start procedure occurs when the receiver is ret without disturbing any data held by the receiver. This can be done by toggling the system power on H/W side or lecting hot start mode in the analyzer software on S/W side.
Warm start
A Warm start procedure occurs when the receiver is ret but with invalid ephemeris data. This test is similar to keeping the receiver to be left off overnight, when almanac data, time and last known position are still valid.
Cold start
Cold start procedure occurs when the receiver is ret and no aiding data is available. This test is similar to the receiver being powered in the first time. On MDT(phone), this can be achieved by disconnecting the power while the main power (battery) is removed without information. (no store command)
Condition of Cold, Warm and Hot start are related to ION-101 Reference [12] specification, and are defined by the availability and age of stored information.
