ANSWER: GPS satellites, starting electronic forum

Fahim

Mr. RP.. i have a suggestion. if your question is not answered in 24 or so hours you should answer it yourself and pose next question...... is dat ok???

---

RP
Good suggestion

Thats a good suggestion. GPS are global positioning system satellites.
They are indeed geo-stationary.

All others open to pose your questions...


---

anil

What is GPS? Are they Ge-stationary?

GPS is abbreviated as Global Positioning System. It is located at a height of 20,000 km from above the earth. Since, there are totally 29 satellites (24 healthy + 3 standby and 2 are unhealthy) across the globe launched by DoD, USA but we are using 24 satellites. These 24 satellites are placed in 6 orbital planes and it uses Earth centred - earth fixed co-ordinate system.

The GPS satellites are not Geo-stationary. These satellites are placed in MEO orbit. To receive GPS signal atleast minimum of 4 satellites view is compulsory to get good accuracy. These satellites uses L-band (L1 and L2 frequencies)

Types of GPS receivers:

(1). Single frequency hand held GPS receiver
(2). Dual frequency GPS receiver.

The GPS satellites are used to find the User position. It gives latitude, longitude and altitude. Main applications include Navigation, Communication and Surveillance.

For more information: ISRO and AAI are planning to launch WAAS (Wide Area Augmentation System) by augmeting GPS satellites with the Ge-stationary satellites.

---

RP
Great info Anil. Thanks for pitching in. In addition to regular geo stationary sats, there are some control satellites that are geostationary in GPS mission.

Now, ISRO scientists develop hydrogen fuel cells to power bus

India's space scientists have developed hydrogen fuel cells to power an automobile bus by leveraging their know-how of the homegrown cryogenic technology for rockets.

The two-year effort has yielded positive results and the scientists are now readying for the fuel cells to be fitted into a bus.

ISRO and Tata Motors entered into an MoU in 2006 to design and develop an automobile bus using hydrogen as a fuel through fuel cell route. Tatas are taking the responsibility for the locomotive part of it, and hydrogen handling system also.

First protomodel has been assembled. Results are good. May be next year, it should be on the road.