Taiwanese vendor SkyTraq has announced what it claims to be the world's highest-integration single-chip GPS receiver. The Linux-compatible Venus634LP measures one square centimeter, and integrates an LNA (low noise amplifier), SAW (surface acoustic wave) filter, GPS RF front end, and Venus6 baseband processor.

(Click here for a larger view of SkyTraq's Venus634LP)

The Venus634LP is comparable to SiRF's extremely popular starIII in that it is a non-hosted design that requires no drivers. GPS data in the form of standard NMEA “sentences” is simply sent to the host operating system from the GPS receiver via a standard UART, according to SkyTraq. Thus, it's said, adding a complete GPS receiver to an existing design requires only the Venus634LP and an active or passive antenna.

A block diagram of SkyTraq's Venus 634LP
(Click to enlarge)
As the block diagram above shows, from left to right, the Venus 634LP integrates a LNA, SAW filter, GPS RF front end, and Venus6 baseband processor. It also includes a 0.5ppm TXCO (temperature compensated crystal oscillator), 32.768kHz RTC crystal, and an LDO (low drop out) regulator.

The RoHS-compliant Venus 634LP comes in a 44-pin LGA (land grid array) package, measuring 10 x 10 x 1.2mm. Acceptable supply voltage ranges from 2.7 to 3.3V, and current consumption is rated at approximately 30mA during satellite tracking and 50mA during acquisition.

SkyTraq says the Venus 634LP has a dedicated massive-correlator signal parameter search engine, which allows rapid acquisition of satellites on up to 51 channels, and continuous tracking on 14 channels. Capable of operating in deep foliage and “urban canyons,” the Venus 634LP can do a cold start in under 30 seconds, and a hot start in under one second, the company claims.

Features and specifications listed by SkyTraq for the Venus 634LP include:

• 51-channel acquisition engine
  
• 14 channel track engine
  
• 8 million time-frequency hypothesis testing per sec
  
• Open sky hot start — 1 second
  
• Open sky cold start — 29 second
  
• Signal detection — better than -158dBm
  
• Reacquisition sensitivity — -155dBm
  
• Accuracy — 2.5m CEP (circular error probable)
  
• Update rate — 1Hz standard
  
• Serial interface — LVTTL level
  
• Protocol — NMEA-0183 V3.01, SkyTraq binary
  
• Current consumption — ~30mA tracking, ~50mA acquisition

The Venus 634LP is compatible with most operating systems, including Linux, Windows Mobile, and Windows XP Embedded. Engineering samples, datasheet, a reference design, and an evaluation kit will be available in June, and volume deliveries are planned for the third quarter. Pricing was not provided.

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