GPS Device - Essay Example

29 April 28, 2007 GPS Device Ans 2a: Since the GPS is designed to target mainly for outdoor use world-wide over a wide range of weather conditions hence it must meet the following physical and environmental specifications. Physical Specifications Enclosure Fully-gasketed, High impact plastic alloy, waterproof to IPX7 standards Dimensions 4.5"H x 2.3"W x 1.6" D, 7”H with antenna (11.4x5.8x4.1; 17.8cm) Weight 236 grams (7.6 ounce) with batteries Environmental Operating Temperature -20° C to +70° C Storage Temperature -40° C to +95° C Vibration -3 dB/octave 100 Hz to 900 Hz Operating Humidity 5% to 95% R.H. non-condensing, at +60 The above mentioned specifications can be achieve if we follow the following design strategies as given in chart 1.

In the column 1 of chart the design attribute are given, while column two gives key design features and sub-features that should be consider during design process. The 3rd column gives the expected likelihoods. Design Attribute Design Considerations Likelihood Environment Aesthetic Design The positioning and size of user interface that governs the overall commercial appearance and ergonomics should be attractive and alluring. Cosmetic Finish Materials High impact plastic alloy, Processes Paint,  rubber  coating User  Safety   Free from any  sharp  edges  and  corners    Durability   Strength Can withstand high impacts and stresses Aging Enclosure has sufficient resistance against yellowing or dulling of  plastic alloy    Water Proofing Waterproof to IPX7 standards  Resistance Have grounding  and  earth  protection    Climate Thermal Effect Temperature Ranges Transportation Temperature≥ Storage Temperature > Operating Temperature Thermal Shocks Can sustain sever cooling or heating slope Vibration Effects Can sustain vibration factors such as displacement-t, velocity, acceleration, and force Reliability Level of reliability High Failure Rate Should be 0.1∼ 0.001% failures per thousand hours Mean time to failure (MTTF) Have large value and be given in years Mean time to repair (MTTR) Have a small value Mean time between failures (MTBF)   ≥ MTTF Design Strategy Chart Ans 2b (i): Following are main blocks of design that meet the given product Specifications. (ii): In following block diagram there are five components blocks.

The outer most blocks represents the housing of to temperature chamber. Its functions is Fig: Temperature Cycling Chamber Block diagram to accommodate internal chambers and control circuitry and protect them against outside environmental factors. Inside the main block we have vapor-tight interior steel liner. The 100% stainless steel liner provides strength to outside housing and a non-corrosive atmosphere to internal chambers and control circuitry. The alpha numeric display is visualize outside the main block.

The arrow head represents its linkage with main control system. Chamber control system provide fully automatic PID through user-friendly alpha numeric display.